<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with Wdesk from Workiva-->
<!-- -->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <link:roleRef roleURI="http://www.acuitybrands.com/role/CommitmentsAndContingencies" xlink:href="ayi-20171130.xsd#CommitmentsAndContingencies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/CommitmentsAndContingenciesDetails" xlink:href="ayi-20171130.xsd#CommitmentsAndContingenciesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/CommitmentsAndContingenciesTables" xlink:href="ayi-20171130.xsd#CommitmentsAndContingenciesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ComprehensiveIncome" xlink:href="ayi-20171130.xsd#ComprehensiveIncome" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ComprehensiveIncomeChangesInComponentsOfAccumulatedOtherComprehensiveIncomeLossItemsDetails" xlink:href="ayi-20171130.xsd#ComprehensiveIncomeChangesInComponentsOfAccumulatedOtherComprehensiveIncomeLossItemsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ComprehensiveIncomeTables" xlink:href="ayi-20171130.xsd#ComprehensiveIncomeTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ComprehensiveIncomeTaxAmountsAllocatedToComponentsOfOtherComprehensiveIncomeLossDetails" xlink:href="ayi-20171130.xsd#ComprehensiveIncomeTaxAmountsAllocatedToComponentsOfOtherComprehensiveIncomeLossDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ConsolidatedBalanceSheets" xlink:href="ayi-20171130.xsd#ConsolidatedBalanceSheets" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:href="ayi-20171130.xsd#ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ConsolidatedStatementsOfCashFlowsUnaudited" xlink:href="ayi-20171130.xsd#ConsolidatedStatementsOfCashFlowsUnaudited" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ConsolidatedStatementsOfComprehensiveIncomeUnaudited" xlink:href="ayi-20171130.xsd#ConsolidatedStatementsOfComprehensiveIncomeUnaudited" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/Debt" xlink:href="ayi-20171130.xsd#Debt" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/DebtDetails" xlink:href="ayi-20171130.xsd#DebtDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/DebtTables" xlink:href="ayi-20171130.xsd#DebtTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/DescriptionOfBusinessAndBasisOfPresentation" xlink:href="ayi-20171130.xsd#DescriptionOfBusinessAndBasisOfPresentation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/DescriptionOfBusinessAndBasisOfPresentationDetails" xlink:href="ayi-20171130.xsd#DescriptionOfBusinessAndBasisOfPresentationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/DocumentAndEntityInformation" xlink:href="ayi-20171130.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/EarningsPerShare" xlink:href="ayi-20171130.xsd#EarningsPerShare" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/EarningsPerShareAntidilutiveSecuritiesExcludedFromEpsComputationDetails" xlink:href="ayi-20171130.xsd#EarningsPerShareAntidilutiveSecuritiesExcludedFromEpsComputationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/EarningsPerShareBasicAndDilutedEarningsPerShareTreasuryStockMethodDetails" xlink:href="ayi-20171130.xsd#EarningsPerShareBasicAndDilutedEarningsPerShareTreasuryStockMethodDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/EarningsPerShareTables" xlink:href="ayi-20171130.xsd#EarningsPerShareTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/FairValueMeasurements" xlink:href="ayi-20171130.xsd#FairValueMeasurements" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/FairValueMeasurementsDetails" xlink:href="ayi-20171130.xsd#FairValueMeasurementsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/FairValueMeasurementsTables" xlink:href="ayi-20171130.xsd#FairValueMeasurementsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/GoodwillAndIntangibleAssets" xlink:href="ayi-20171130.xsd#GoodwillAndIntangibleAssets" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/GoodwillAndIntangibleAssetsChangesInGoodwillDetails" xlink:href="ayi-20171130.xsd#GoodwillAndIntangibleAssetsChangesInGoodwillDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/GoodwillAndIntangibleAssetsDetails" xlink:href="ayi-20171130.xsd#GoodwillAndIntangibleAssetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/GoodwillAndIntangibleAssetsTables" xlink:href="ayi-20171130.xsd#GoodwillAndIntangibleAssetsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/Inventories" xlink:href="ayi-20171130.xsd#Inventories" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/InventoriesDetails" xlink:href="ayi-20171130.xsd#InventoriesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/InventoriesTables" xlink:href="ayi-20171130.xsd#InventoriesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/NewAccountingPronouncements" xlink:href="ayi-20171130.xsd#NewAccountingPronouncements" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/NewAccountingPronouncementsDetails" xlink:href="ayi-20171130.xsd#NewAccountingPronouncementsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/PensionPlans" xlink:href="ayi-20171130.xsd#PensionPlans" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/PensionPlansDetails" xlink:href="ayi-20171130.xsd#PensionPlansDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/PensionPlansTables" xlink:href="ayi-20171130.xsd#PensionPlansTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ShareBasedPayments" xlink:href="ayi-20171130.xsd#ShareBasedPayments" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ShareBasedPaymentsDetails" xlink:href="ayi-20171130.xsd#ShareBasedPaymentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ShareBasedPaymentsTables" xlink:href="ayi-20171130.xsd#ShareBasedPaymentsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SignificantAccountingPolicies" xlink:href="ayi-20171130.xsd#SignificantAccountingPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SignificantAccountingPoliciesPolicies" xlink:href="ayi-20171130.xsd#SignificantAccountingPoliciesPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SpecialCharge" xlink:href="ayi-20171130.xsd#SpecialCharge" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SpecialChargeDetails" xlink:href="ayi-20171130.xsd#SpecialChargeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SpecialChargeTables" xlink:href="ayi-20171130.xsd#SpecialChargeTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SubsequentEvents" xlink:href="ayi-20171130.xsd#SubsequentEvents" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SubsequentEventsDetails" xlink:href="ayi-20171130.xsd#SubsequentEventsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatements" xlink:href="ayi-20171130.xsd#SupplementalGuarantorCondensedConsolidatingFinancialStatements" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatementsBalanceSheetsDetails" xlink:href="ayi-20171130.xsd#SupplementalGuarantorCondensedConsolidatingFinancialStatementsBalanceSheetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatementsCashFlowsDetails" xlink:href="ayi-20171130.xsd#SupplementalGuarantorCondensedConsolidatingFinancialStatementsCashFlowsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatementsIncomeDetails" xlink:href="ayi-20171130.xsd#SupplementalGuarantorCondensedConsolidatingFinancialStatementsIncomeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatementsTables" xlink:href="ayi-20171130.xsd#SupplementalGuarantorCondensedConsolidatingFinancialStatementsTables" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/CommitmentsAndContingencies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/CommitmentsAndContingenciesDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/CommitmentsAndContingenciesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ComprehensiveIncome" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ComprehensiveIncomeChangesInComponentsOfAccumulatedOtherComprehensiveIncomeLossItemsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_0EB27EB6B4F2E1B583BADBC7EDC2A50C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_9BA6C530494C74EFA996DBC7EDC25542" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_0EB27EB6B4F2E1B583BADBC7EDC2A50C" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_9BA6C530494C74EFA996DBC7EDC25542" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_3B4A318D862E169E7FA1DBC7EDC2511D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_9BA6C530494C74EFA996DBC7EDC25542" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_3B4A318D862E169E7FA1DBC7EDC2511D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_3E70CF2CEEDD64240689DBC7EDC27FBC_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_3B4A318D862E169E7FA1DBC7EDC2511D" xlink:to="loc_us-gaap_EquityComponentDomain_3E70CF2CEEDD64240689DBC7EDC27FBC_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_3E70CF2CEEDD64240689DBC7EDC27FBC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_3B4A318D862E169E7FA1DBC7EDC2511D" xlink:to="loc_us-gaap_EquityComponentDomain_3E70CF2CEEDD64240689DBC7EDC27FBC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_CF4D7A0B44AE6E7BE67DDBC7EDC23C7B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_3E70CF2CEEDD64240689DBC7EDC27FBC" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_CF4D7A0B44AE6E7BE67DDBC7EDC23C7B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedTranslationAdjustmentMember" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_45ECE70BD7C6B6BAC97EDBC7EDC2214C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_CF4D7A0B44AE6E7BE67DDBC7EDC23C7B" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_45ECE70BD7C6B6BAC97EDBC7EDC2214C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_78351B588F4F869C187ADBC7EDC22639" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_CF4D7A0B44AE6E7BE67DDBC7EDC23C7B" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_78351B588F4F869C187ADBC7EDC22639" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AOCIAttributableToParentNetOfTaxRollForward" xlink:label="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_B267773DEE402611A99BDBC7EDC2011A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_0EB27EB6B4F2E1B583BADBC7EDC2A50C" xlink:to="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_B267773DEE402611A99BDBC7EDC2011A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_B85326E73D3BDFB76D5CDBC7EDC2C20D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_B267773DEE402611A99BDBC7EDC2011A" xlink:to="loc_us-gaap_StockholdersEquity_B85326E73D3BDFB76D5CDBC7EDC2C20D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_138ABC6BAC97AAEB76E3DBC7EDC23BA2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_B267773DEE402611A99BDBC7EDC2011A" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_138ABC6BAC97AAEB76E3DBC7EDC23BA2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_802A6E1E7BFDDBF45EFDDBC7EDC21118" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_B267773DEE402611A99BDBC7EDC2011A" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_802A6E1E7BFDDBF45EFDDBC7EDC21118" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_B18096EAF5E862062513DBC7EDC2EAF9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_B267773DEE402611A99BDBC7EDC2011A" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_B18096EAF5E862062513DBC7EDC2EAF9" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ComprehensiveIncomeTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ComprehensiveIncomeTaxAmountsAllocatedToComponentsOfOtherComprehensiveIncomeLossDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_DD9A33EBD13CDD7E11B9D7D8EADB8998" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_E0E79506F2831DE6AECFD7D8EAD8020C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_DD9A33EBD13CDD7E11B9D7D8EADB8998" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_E0E79506F2831DE6AECFD7D8EAD8020C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_50CDF3AC20FF34726995D7D8EAD8A8B3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_E0E79506F2831DE6AECFD7D8EAD8020C" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_50CDF3AC20FF34726995D7D8EAD8A8B3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_1BEAD7F9697CE76CE678D7D8EAD93338_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_50CDF3AC20FF34726995D7D8EAD8A8B3" xlink:to="loc_us-gaap_EquityComponentDomain_1BEAD7F9697CE76CE678D7D8EAD93338_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_1BEAD7F9697CE76CE678D7D8EAD93338" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_50CDF3AC20FF34726995D7D8EAD8A8B3" xlink:to="loc_us-gaap_EquityComponentDomain_1BEAD7F9697CE76CE678D7D8EAD93338" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_0FAC7BF1D25795C3667FD7D8EAD9FD1F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_1BEAD7F9697CE76CE678D7D8EAD93338" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_0FAC7BF1D25795C3667FD7D8EAD9FD1F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedTranslationAdjustmentMember" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_E7A4EBFAB082BA74367ED7D8EADAED98" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_0FAC7BF1D25795C3667FD7D8EAD9FD1F" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_E7A4EBFAB082BA74367ED7D8EADAED98" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_EA655B6F9E1DE35EA254D7D8EADADA92" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_0FAC7BF1D25795C3667FD7D8EAD9FD1F" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_EA655B6F9E1DE35EA254D7D8EADADA92" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember_8D64A55360674BB32AA3D7D8EADB07D1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_EA655B6F9E1DE35EA254D7D8EADADA92" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember_8D64A55360674BB32AA3D7D8EADB07D1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember_FC5CD53BDF9110DCA78AD7D8EADB4799" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_EA655B6F9E1DE35EA254D7D8EADADA92" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember_FC5CD53BDF9110DCA78AD7D8EADB4799" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_698E57A7C08AC074D0CDD7D8EADB6C92" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_DD9A33EBD13CDD7E11B9D7D8EADB8998" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_698E57A7C08AC074D0CDD7D8EADB6C92" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTax_BBC2C18B3DEF4BED2F12D7D8EADB3050" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_DD9A33EBD13CDD7E11B9D7D8EADB8998" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTax_BBC2C18B3DEF4BED2F12D7D8EADB3050" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_66095ADBE47A110BF73FD7D8EADB36C4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_DD9A33EBD13CDD7E11B9D7D8EADB8998" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_66095ADBE47A110BF73FD7D8EADB36C4" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ConsolidatedBalanceSheets" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ConsolidatedStatementsOfCashFlowsUnaudited" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ConsolidatedStatementsOfComprehensiveIncomeUnaudited" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/Debt" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/DebtDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_10652F031028C1FECF7BC740AF62E3FD" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_96F0DFE8E0E6C2E3B4CDC740AF61FA74" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_10652F031028C1FECF7BC740AF62E3FD" xlink:to="loc_us-gaap_DebtInstrumentTable_96F0DFE8E0E6C2E3B4CDC740AF61FA74" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_89F51AD369CBB0D70CB9C740AF612D0A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_96F0DFE8E0E6C2E3B4CDC740AF61FA74" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_89F51AD369CBB0D70CB9C740AF612D0A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_A588F87CF6429DEB4928C740AF61E649_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_89F51AD369CBB0D70CB9C740AF612D0A" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_A588F87CF6429DEB4928C740AF61E649_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_A588F87CF6429DEB4928C740AF61E649" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_89F51AD369CBB0D70CB9C740AF612D0A" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_A588F87CF6429DEB4928C740AF61E649" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditMember" xlink:label="loc_us-gaap_LineOfCreditMember_E33367E1166E7169CC3CC740AF61A320" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_A588F87CF6429DEB4928C740AF61E649" xlink:to="loc_us-gaap_LineOfCreditMember_E33367E1166E7169CC3CC740AF61A320" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LetterOfCreditMember" xlink:label="loc_us-gaap_LetterOfCreditMember_2F472BF4BD19FA706AB8C740AF61E113" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_A588F87CF6429DEB4928C740AF61E649" xlink:to="loc_us-gaap_LetterOfCreditMember_2F472BF4BD19FA706AB8C740AF61E113" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="loc_us-gaap_SeniorNotesMember_D73819542C0015D6DA1CC740AF6145E2" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_A588F87CF6429DEB4928C740AF61E649" xlink:to="loc_us-gaap_SeniorNotesMember_D73819542C0015D6DA1CC740AF6145E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NontaxableMunicipalBondsMember" xlink:label="loc_us-gaap_NontaxableMunicipalBondsMember_4CFC1E6E313A9597584AC740AF615C1E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_A588F87CF6429DEB4928C740AF61E649" xlink:to="loc_us-gaap_NontaxableMunicipalBondsMember_4CFC1E6E313A9597584AC740AF615C1E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BankLoanObligationsMember" xlink:label="loc_us-gaap_BankLoanObligationsMember_E6A94CE9F721AF890E8BC740AF61F5F3" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_A588F87CF6429DEB4928C740AF61E649" xlink:to="loc_us-gaap_BankLoanObligationsMember_E6A94CE9F721AF890E8BC740AF61F5F3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_E1A8AF101EA344F049EDC740AF61214D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_96F0DFE8E0E6C2E3B4CDC740AF61FA74" xlink:to="loc_us-gaap_DebtInstrumentAxis_E1A8AF101EA344F049EDC740AF61214D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_2E0DBD3441775602BBBBC740AF613BE9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_E1A8AF101EA344F049EDC740AF61214D" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_2E0DBD3441775602BBBBC740AF613BE9_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_2E0DBD3441775602BBBBC740AF613BE9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_E1A8AF101EA344F049EDC740AF61214D" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_2E0DBD3441775602BBBBC740AF613BE9" xlink:type="arc" />
    <link:loc xlink:href="ayi-20171130.xsd#ayi_RevolvingCreditFacilityMaturingAugust272019Member" xlink:label="loc_ayi_RevolvingCreditFacilityMaturingAugust272019Member_38ABAEC4A8B137812694C740AF61C1A7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2E0DBD3441775602BBBBC740AF613BE9" xlink:to="loc_ayi_RevolvingCreditFacilityMaturingAugust272019Member_38ABAEC4A8B137812694C740AF61C1A7" xlink:type="arc" />
    <link:loc xlink:href="ayi-20171130.xsd#ayi_SeniorUnsecuredNotesMaturingDecember2019Member" xlink:label="loc_ayi_SeniorUnsecuredNotesMaturingDecember2019Member_2AD7E2B4348FA8200FFBC740AF613A8D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2E0DBD3441775602BBBBC740AF613BE9" xlink:to="loc_ayi_SeniorUnsecuredNotesMaturingDecember2019Member_2AD7E2B4348FA8200FFBC740AF613A8D" xlink:type="arc" />
    <link:loc xlink:href="ayi-20171130.xsd#ayi_IndustrialRevenueBondMaturingin2021Member" xlink:label="loc_ayi_IndustrialRevenueBondMaturingin2021Member_E208775C27698550A6C4C740AF6127BD" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2E0DBD3441775602BBBBC740AF613BE9" xlink:to="loc_ayi_IndustrialRevenueBondMaturingin2021Member_E208775C27698550A6C4C740AF6127BD" xlink:type="arc" />
    <link:loc xlink:href="ayi-20171130.xsd#ayi_A2016FixedrateBankLoansMember" xlink:label="loc_ayi_A2016FixedrateBankLoansMember_4CD493C726A4E595450EC740AF619DC6" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2E0DBD3441775602BBBBC740AF613BE9" xlink:to="loc_ayi_A2016FixedrateBankLoansMember_4CD493C726A4E595450EC740AF619DC6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_37F679D791AD2F23D4FFC740AF622E2F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_96F0DFE8E0E6C2E3B4CDC740AF61FA74" xlink:to="loc_us-gaap_RangeAxis_37F679D791AD2F23D4FFC740AF622E2F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_A3512265CCB252E1CA75C740AF629BFA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_37F679D791AD2F23D4FFC740AF622E2F" xlink:to="loc_us-gaap_RangeMember_A3512265CCB252E1CA75C740AF629BFA_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_A3512265CCB252E1CA75C740AF629BFA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_37F679D791AD2F23D4FFC740AF622E2F" xlink:to="loc_us-gaap_RangeMember_A3512265CCB252E1CA75C740AF629BFA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_604D666CC13EDFA7AE81C740AF62699B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_A3512265CCB252E1CA75C740AF629BFA" xlink:to="loc_us-gaap_MinimumMember_604D666CC13EDFA7AE81C740AF62699B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_B68A39FA5C749500F0E1C740AF6200CA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_A3512265CCB252E1CA75C740AF629BFA" xlink:to="loc_us-gaap_MaximumMember_B68A39FA5C749500F0E1C740AF6200CA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityAbstract" xlink:label="loc_us-gaap_LineOfCreditFacilityAbstract_40B60D3FE15937150288C740AF6282B6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_10652F031028C1FECF7BC740AF62E3FD" xlink:to="loc_us-gaap_LineOfCreditFacilityAbstract_40B60D3FE15937150288C740AF6282B6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_8642B994BA4E7A542790C740AF629CBD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_40B60D3FE15937150288C740AF6282B6" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_8642B994BA4E7A542790C740AF629CBD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCredit" xlink:label="loc_us-gaap_LineOfCredit_796FC30CA2D0C04B5926C740AF62F319" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_40B60D3FE15937150288C740AF6282B6" xlink:to="loc_us-gaap_LineOfCredit_796FC30CA2D0C04B5926C740AF62F319" xlink:type="arc" />
    <link:loc xlink:href="ayi-20171130.xsd#ayi_LineofCreditFacilityInterestCoverageRatio" xlink:label="loc_ayi_LineofCreditFacilityInterestCoverageRatio_A4630376F3C428B10A8FC740AF626D73" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_40B60D3FE15937150288C740AF6282B6" xlink:to="loc_ayi_LineofCreditFacilityInterestCoverageRatio_A4630376F3C428B10A8FC740AF626D73" xlink:type="arc" />
    <link:loc xlink:href="ayi-20171130.xsd#ayi_LineofCreditFacilityLeverageRatioIndebtednesstoEBITDA" xlink:label="loc_ayi_LineofCreditFacilityLeverageRatioIndebtednesstoEBITDA_502F6EB4510D3A131360C740AF628A79" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_40B60D3FE15937150288C740AF6282B6" xlink:to="loc_ayi_LineofCreditFacilityLeverageRatioIndebtednesstoEBITDA_502F6EB4510D3A131360C740AF628A79" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_910EEDE16DB1492A101BC740AF62816B" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_40B60D3FE15937150288C740AF6282B6" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_910EEDE16DB1492A101BC740AF62816B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_CCAEFAABABB1BEF73E40C740AF62D819" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_40B60D3FE15937150288C740AF6282B6" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_CCAEFAABABB1BEF73E40C740AF62D819" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_34D56AEEFFA417307508C740AF62ECC3" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_40B60D3FE15937150288C740AF6282B6" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_34D56AEEFFA417307508C740AF62ECC3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_53D4A13F16BC4E153A7BC740AF62563A" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_40B60D3FE15937150288C740AF6282B6" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_53D4A13F16BC4E153A7BC740AF62563A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentsAbstract" xlink:label="loc_us-gaap_DebtInstrumentsAbstract_D61375DCD117F980B121C740AF62FCB7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_10652F031028C1FECF7BC740AF62E3FD" xlink:to="loc_us-gaap_DebtInstrumentsAbstract_D61375DCD117F980B121C740AF62FCB7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_0FC49F880537B7FC465EC740AF62A434" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentsAbstract_D61375DCD117F980B121C740AF62FCB7" xlink:to="loc_us-gaap_LongTermDebt_0FC49F880537B7FC465EC740AF62A434" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_6A55C653AC4E554593A2C740AF622187" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentsAbstract_D61375DCD117F980B121C740AF62FCB7" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_6A55C653AC4E554593A2C740AF622187" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestRevenueOrExpenseNetAbstract" xlink:label="loc_us-gaap_InterestRevenueOrExpenseNetAbstract_74B20CE4237B4BD78668C740AF627F71" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_10652F031028C1FECF7BC740AF62E3FD" xlink:to="loc_us-gaap_InterestRevenueOrExpenseNetAbstract_74B20CE4237B4BD78668C740AF627F71" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_A7DF12C9F10EEC1AA4E6C740AF63A1C9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestRevenueOrExpenseNetAbstract_74B20CE4237B4BD78668C740AF627F71" xlink:to="loc_us-gaap_InterestExpense_A7DF12C9F10EEC1AA4E6C740AF63A1C9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="loc_us-gaap_InvestmentIncomeInterest_A9F69706AA6B38E7F8BFC740AF636486" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestRevenueOrExpenseNetAbstract_74B20CE4237B4BD78668C740AF627F71" xlink:to="loc_us-gaap_InvestmentIncomeInterest_A9F69706AA6B38E7F8BFC740AF636486" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestRevenueExpenseNet" xlink:label="loc_us-gaap_InterestRevenueExpenseNet_0F267E6765C05982F10BC740AF63EC97" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestRevenueOrExpenseNetAbstract_74B20CE4237B4BD78668C740AF627F71" xlink:to="loc_us-gaap_InterestRevenueExpenseNet_0F267E6765C05982F10BC740AF63EC97" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/DebtTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/DescriptionOfBusinessAndBasisOfPresentation" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/DescriptionOfBusinessAndBasisOfPresentationDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/DocumentAndEntityInformation" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/EarningsPerShare" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/EarningsPerShareAntidilutiveSecuritiesExcludedFromEpsComputationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_F62D3756DFD02ED8FC95DBC7EDDE3D88" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_82ECC77CD6E29F6D3816DBC7EDDE8486" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_F62D3756DFD02ED8FC95DBC7EDDE3D88" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_82ECC77CD6E29F6D3816DBC7EDDE8486" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_89F1B4E9261774866D14DBC7EDDE2A62" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_82ECC77CD6E29F6D3816DBC7EDDE8486" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_89F1B4E9261774866D14DBC7EDDE2A62" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_16CBA1E28EF73FB254D4DBC7EDDE197B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_89F1B4E9261774866D14DBC7EDDE2A62" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_16CBA1E28EF73FB254D4DBC7EDDE197B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_16CBA1E28EF73FB254D4DBC7EDDE197B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_89F1B4E9261774866D14DBC7EDDE2A62" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_16CBA1E28EF73FB254D4DBC7EDDE197B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_865F137BF6DC339DE785DBC7EDDE2AE2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_16CBA1E28EF73FB254D4DBC7EDDE197B" xlink:to="loc_us-gaap_EmployeeStockOptionMember_865F137BF6DC339DE785DBC7EDDE2AE2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="loc_us-gaap_RestrictedStockMember_67C079358EFEF80A2599DBC7EDDED65B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_16CBA1E28EF73FB254D4DBC7EDDE197B" xlink:to="loc_us-gaap_RestrictedStockMember_67C079358EFEF80A2599DBC7EDDED65B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_3F3EA2A9AE6368C389F0DBC7EDDECC0E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_F62D3756DFD02ED8FC95DBC7EDDE3D88" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_3F3EA2A9AE6368C389F0DBC7EDDECC0E" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/EarningsPerShareBasicAndDilutedEarningsPerShareTreasuryStockMethodDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/EarningsPerShareTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/FairValueMeasurements" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/FairValueMeasurementsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_7587E4A41BE0B368B31DC72964574C11" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_9D464C7C4243FEA6AB16C7296456401C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_7587E4A41BE0B368B31DC72964574C11" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_9D464C7C4243FEA6AB16C7296456401C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_4C9DB320C5A16227F6DFC7296456EC35" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_9D464C7C4243FEA6AB16C7296456401C" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_4C9DB320C5A16227F6DFC7296456EC35" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_BF5FEEB26683A52FCB53C72964563107_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_4C9DB320C5A16227F6DFC7296456EC35" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_BF5FEEB26683A52FCB53C72964563107_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_2A06EF00011D97B9BB48C7296456EC1D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_4C9DB320C5A16227F6DFC7296456EC35" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_2A06EF00011D97B9BB48C7296456EC1D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_BF5FEEB26683A52FCB53C72964563107" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_2A06EF00011D97B9BB48C7296456EC1D" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_BF5FEEB26683A52FCB53C72964563107" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_CD9590043868DA3433A7C72964569A93" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_BF5FEEB26683A52FCB53C72964563107" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_CD9590043868DA3433A7C72964569A93" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_E6C68129922606194EBDC72964563428" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_BF5FEEB26683A52FCB53C72964563107" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_E6C68129922606194EBDC72964563428" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_03E8081D318A90FD8C5CC7296456AB07" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_9D464C7C4243FEA6AB16C7296456401C" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_03E8081D318A90FD8C5CC7296456AB07" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_AAA3B1B605C4D4626B15C72964561E9D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_03E8081D318A90FD8C5CC7296456AB07" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_AAA3B1B605C4D4626B15C72964561E9D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_AAA3B1B605C4D4626B15C72964561E9D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_03E8081D318A90FD8C5CC7296456AB07" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_AAA3B1B605C4D4626B15C72964561E9D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_D8985A19F199FDD6159BC7296456AE37" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_AAA3B1B605C4D4626B15C72964561E9D" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_D8985A19F199FDD6159BC7296456AE37" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_A514DBB1C7CDE8CC2E68C72964565D06" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_9D464C7C4243FEA6AB16C7296456401C" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_A514DBB1C7CDE8CC2E68C72964565D06" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_48222BE38F2671075C85C7296456F18D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_A514DBB1C7CDE8CC2E68C72964565D06" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_48222BE38F2671075C85C7296456F18D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_48222BE38F2671075C85C7296456F18D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_A514DBB1C7CDE8CC2E68C72964565D06" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_48222BE38F2671075C85C7296456F18D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="loc_us-gaap_SeniorNotesMember_9A66BD07C6F732D5E915C72964562CC0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_48222BE38F2671075C85C7296456F18D" xlink:to="loc_us-gaap_SeniorNotesMember_9A66BD07C6F732D5E915C72964562CC0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NontaxableMunicipalBondsMember" xlink:label="loc_us-gaap_NontaxableMunicipalBondsMember_6F12E83DBC050306CF9DC72964562610" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_48222BE38F2671075C85C7296456F18D" xlink:to="loc_us-gaap_NontaxableMunicipalBondsMember_6F12E83DBC050306CF9DC72964562610" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BankLoanObligationsMember" xlink:label="loc_us-gaap_BankLoanObligationsMember_3B383DA4E7909C441AD7C7296457D43D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_48222BE38F2671075C85C7296456F18D" xlink:to="loc_us-gaap_BankLoanObligationsMember_3B383DA4E7909C441AD7C7296457D43D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_F7C7080E2CBB1253AC8CC72964572077" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_9D464C7C4243FEA6AB16C7296456401C" xlink:to="loc_us-gaap_DebtInstrumentAxis_F7C7080E2CBB1253AC8CC72964572077" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_D993FE3E92F6C97A34BDC72964579510_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_F7C7080E2CBB1253AC8CC72964572077" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_D993FE3E92F6C97A34BDC72964579510_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_D993FE3E92F6C97A34BDC72964579510" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_F7C7080E2CBB1253AC8CC72964572077" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_D993FE3E92F6C97A34BDC72964579510" xlink:type="arc" />
    <link:loc xlink:href="ayi-20171130.xsd#ayi_IndustrialRevenueBondMaturingin2021Member" xlink:label="loc_ayi_IndustrialRevenueBondMaturingin2021Member_E4D68A798CE9B4A69D25C72964571FFD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_D993FE3E92F6C97A34BDC72964579510" xlink:to="loc_ayi_IndustrialRevenueBondMaturingin2021Member_E4D68A798CE9B4A69D25C72964571FFD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_C56BAEA082644D071735C729645706FE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_7587E4A41BE0B368B31DC72964574C11" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_C56BAEA082644D071735C729645706FE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_4E999286B0A43B27ACB9C7296457E9F8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_7587E4A41BE0B368B31DC72964574C11" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_4E999286B0A43B27ACB9C7296457E9F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtFairValue" xlink:label="loc_us-gaap_LongTermDebtFairValue_CAA60C08870755A86EF0C72964571934" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_4E999286B0A43B27ACB9C7296457E9F8" xlink:to="loc_us-gaap_LongTermDebtFairValue_CAA60C08870755A86EF0C72964571934" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/FairValueMeasurementsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/GoodwillAndIntangibleAssets" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/GoodwillAndIntangibleAssetsChangesInGoodwillDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/GoodwillAndIntangibleAssetsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/GoodwillAndIntangibleAssetsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/Inventories" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/InventoriesDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/InventoriesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/NewAccountingPronouncements" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/NewAccountingPronouncementsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NewAccountingPronouncementEarlyAdoptionLineItems" xlink:label="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionLineItems_414A84D25B3E65E67EDF6B3CEFB5A904" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NewAccountingPronouncementEarlyAdoptionTable" xlink:label="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionTable_79673B289DBAC7C35C956B3CEFB59B77" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionLineItems_414A84D25B3E65E67EDF6B3CEFB5A904" xlink:to="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionTable_79673B289DBAC7C35C956B3CEFB59B77" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_42F71D6F2B5547136B546B3CEFB58C61" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionTable_79673B289DBAC7C35C956B3CEFB59B77" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_42F71D6F2B5547136B546B3CEFB58C61" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_0B77B91821C5CDADE0946B3CEFB54109_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_42F71D6F2B5547136B546B3CEFB58C61" xlink:to="loc_us-gaap_TypeOfAdoptionMember_0B77B91821C5CDADE0946B3CEFB54109_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_0B77B91821C5CDADE0946B3CEFB54109" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_42F71D6F2B5547136B546B3CEFB58C61" xlink:to="loc_us-gaap_TypeOfAdoptionMember_0B77B91821C5CDADE0946B3CEFB54109" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountingStandardsUpdate201609Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201609Member_EA137F7712E79F2B3B726B3CEFB5BCCB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_0B77B91821C5CDADE0946B3CEFB54109" xlink:to="loc_us-gaap_AccountingStandardsUpdate201609Member_EA137F7712E79F2B3B726B3CEFB5BCCB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_9B60B9E9AF74312BFB626B3CEFB673B7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionLineItems_414A84D25B3E65E67EDF6B3CEFB5A904" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_9B60B9E9AF74312BFB626B3CEFB673B7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_9F46245D348C9691DCEC6B3CEFB664A2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionLineItems_414A84D25B3E65E67EDF6B3CEFB5A904" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_9F46245D348C9691DCEC6B3CEFB664A2" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/PensionPlans" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/PensionPlansDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/PensionPlansTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ShareBasedPayments" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ShareBasedPaymentsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ShareBasedPaymentsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SignificantAccountingPolicies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SignificantAccountingPoliciesPolicies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SpecialCharge" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SpecialChargeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCostAndReserveLineItems" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_460E38E19A7B86B73905BE162F555003" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_E52C3E35E87F000BB68ABE162F5572BE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_460E38E19A7B86B73905BE162F555003" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_E52C3E35E87F000BB68ABE162F5572BE" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringPlanAxis" xlink:label="loc_us-gaap_RestructuringPlanAxis_8307F0741C9A5021A142BE1EDCC9DB66" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_E52C3E35E87F000BB68ABE162F5572BE" xlink:to="loc_us-gaap_RestructuringPlanAxis_8307F0741C9A5021A142BE1EDCC9DB66" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringPlanDomain" xlink:label="loc_us-gaap_RestructuringPlanDomain_5A5794B6E77501CA068DBE1F17F2A18A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringPlanAxis_8307F0741C9A5021A142BE1EDCC9DB66" xlink:to="loc_us-gaap_RestructuringPlanDomain_5A5794B6E77501CA068DBE1F17F2A18A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringPlanDomain" xlink:label="loc_us-gaap_RestructuringPlanDomain_5A5794B6E77501CA068DBE1F17F2A18A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringPlanAxis_8307F0741C9A5021A142BE1EDCC9DB66" xlink:to="loc_us-gaap_RestructuringPlanDomain_5A5794B6E77501CA068DBE1F17F2A18A" xlink:type="arc" />
    <link:loc xlink:href="ayi-20171130.xsd#ayi_Fiscal2017ActionsRestructuringActivityMember" xlink:label="loc_ayi_Fiscal2017ActionsRestructuringActivityMember_B915B81DECDC4982B702BE1F97B1C21C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringPlanDomain_5A5794B6E77501CA068DBE1F17F2A18A" xlink:to="loc_ayi_Fiscal2017ActionsRestructuringActivityMember_B915B81DECDC4982B702BE1F97B1C21C" xlink:type="arc" />
    <link:loc xlink:href="ayi-20171130.xsd#ayi_Fiscal2016ActionsRestructuringActivityMember" xlink:label="loc_ayi_Fiscal2016ActionsRestructuringActivityMember_89D4C1E3B73253E0C2DCBE1FCECD497D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringPlanDomain_5A5794B6E77501CA068DBE1F17F2A18A" xlink:to="loc_ayi_Fiscal2016ActionsRestructuringActivityMember_89D4C1E3B73253E0C2DCBE1FCECD497D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_9611F80D01DE2379B343BE162F55A872" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_E52C3E35E87F000BB68ABE162F5572BE" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_9611F80D01DE2379B343BE162F55A872" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_CE16CC4FED18ECDED5A4BE162F5525E5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_9611F80D01DE2379B343BE162F55A872" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_CE16CC4FED18ECDED5A4BE162F5525E5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_CE16CC4FED18ECDED5A4BE162F5525E5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_9611F80D01DE2379B343BE162F55A872" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_CE16CC4FED18ECDED5A4BE162F5525E5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringChargesMember" xlink:label="loc_us-gaap_RestructuringChargesMember_071E424CB00A09EED061BE162F558B2B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_CE16CC4FED18ECDED5A4BE162F5525E5" xlink:to="loc_us-gaap_RestructuringChargesMember_071E424CB00A09EED061BE162F558B2B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCostAndReserveAxis" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_88B2B01D138614047DADBE162F550D7A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_E52C3E35E87F000BB68ABE162F5572BE" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_88B2B01D138614047DADBE162F550D7A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_D5EC8230CA9E4E7760DDBE162F5542E5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_88B2B01D138614047DADBE162F550D7A" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_D5EC8230CA9E4E7760DDBE162F5542E5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_D5EC8230CA9E4E7760DDBE162F5542E5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_88B2B01D138614047DADBE162F550D7A" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_D5EC8230CA9E4E7760DDBE162F5542E5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeSeveranceMember" xlink:label="loc_us-gaap_EmployeeSeveranceMember_C57F821112E462D8EFF7BE162F558F5D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_D5EC8230CA9E4E7760DDBE162F5542E5" xlink:to="loc_us-gaap_EmployeeSeveranceMember_C57F821112E462D8EFF7BE162F558F5D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ContractTerminationMember" xlink:label="loc_us-gaap_ContractTerminationMember_061C681AD4151005AEC3BE162F55148E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_D5EC8230CA9E4E7760DDBE162F5542E5" xlink:to="loc_us-gaap_ContractTerminationMember_061C681AD4151005AEC3BE162F55148E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCharges" xlink:label="loc_us-gaap_RestructuringCharges_B9F9664C049706CB2A11BE162F558AB0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_460E38E19A7B86B73905BE162F555003" xlink:to="loc_us-gaap_RestructuringCharges_B9F9664C049706CB2A11BE162F558AB0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringReserveRollForward" xlink:label="loc_us-gaap_RestructuringReserveRollForward_85428A65D97817AE89ACBE162F55916C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_460E38E19A7B86B73905BE162F555003" xlink:to="loc_us-gaap_RestructuringReserveRollForward_85428A65D97817AE89ACBE162F55916C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringReserve" xlink:label="loc_us-gaap_RestructuringReserve_1EF1B7888E72BF57C82DBE162F55EF60" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_85428A65D97817AE89ACBE162F55916C" xlink:to="loc_us-gaap_RestructuringReserve_1EF1B7888E72BF57C82DBE162F55EF60" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringAndRelatedCostIncurredCost" xlink:label="loc_us-gaap_RestructuringAndRelatedCostIncurredCost_03DA020A69B3F2F388A2BE162F55291F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_85428A65D97817AE89ACBE162F55916C" xlink:to="loc_us-gaap_RestructuringAndRelatedCostIncurredCost_03DA020A69B3F2F388A2BE162F55291F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsForRestructuring" xlink:label="loc_us-gaap_PaymentsForRestructuring_5B63130EBA265F1CC60DBE162F55D668" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_85428A65D97817AE89ACBE162F55916C" xlink:to="loc_us-gaap_PaymentsForRestructuring_5B63130EBA265F1CC60DBE162F55D668" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SpecialChargeTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SubsequentEvents" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SubsequentEventsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventLineItems" xlink:label="loc_us-gaap_SubsequentEventLineItems_3F79692F1530B9FF8CA1B85652C881AA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTable" xlink:label="loc_us-gaap_SubsequentEventTable_CFEC040034FF9E2A4475B85652C20122" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_3F79692F1530B9FF8CA1B85652C881AA" xlink:to="loc_us-gaap_SubsequentEventTable_CFEC040034FF9E2A4475B85652C20122" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_1A1231D86C96556FF5E0B85652C22953" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_CFEC040034FF9E2A4475B85652C20122" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_1A1231D86C96556FF5E0B85652C22953" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_DAAF2BA9DDB536B43F06B85652C84B8F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_1A1231D86C96556FF5E0B85652C22953" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_DAAF2BA9DDB536B43F06B85652C84B8F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_DAAF2BA9DDB536B43F06B85652C84B8F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_1A1231D86C96556FF5E0B85652C22953" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_DAAF2BA9DDB536B43F06B85652C84B8F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_B41D12CB23183CBFB7B5B8582D914D1B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_DAAF2BA9DDB536B43F06B85652C84B8F" xlink:to="loc_us-gaap_SubsequentEventMember_B41D12CB23183CBFB7B5B8582D914D1B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_9EB12D083D5D5ACDD1FBB8570B868C53" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_3F79692F1530B9FF8CA1B85652C881AA" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_9EB12D083D5D5ACDD1FBB8570B868C53" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatements" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatementsBalanceSheetsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedFinancialStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_FD9E690BD08FCB435671C72963C8E110" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfCondensedFinancialStatementsTable" xlink:label="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_EA63AAF930F8330E0595C72963C7B1B1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_FD9E690BD08FCB435671C72963C8E110" xlink:to="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_EA63AAF930F8330E0595C72963C7B1B1" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_7EEFBB496C04D4BB173CC72963C89FAD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_EA63AAF930F8330E0595C72963C7B1B1" xlink:to="loc_us-gaap_ConsolidationItemsAxis_7EEFBB496C04D4BB173CC72963C89FAD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_7A2E09CFF4999963D83DC72963C85CD7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_7EEFBB496C04D4BB173CC72963C89FAD" xlink:to="loc_us-gaap_ConsolidationItemsDomain_7A2E09CFF4999963D83DC72963C85CD7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_7A2E09CFF4999963D83DC72963C85CD7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_7EEFBB496C04D4BB173CC72963C89FAD" xlink:to="loc_us-gaap_ConsolidationItemsDomain_7A2E09CFF4999963D83DC72963C85CD7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_750ABB3E29390E9F9C29C72963C8AEB4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_7A2E09CFF4999963D83DC72963C85CD7" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_750ABB3E29390E9F9C29C72963C8AEB4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_C334511654972E2D53ECC72963C8F56F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_EA63AAF930F8330E0595C72963C7B1B1" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_C334511654972E2D53ECC72963C8F56F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_721AE42F32CC19D73509C72963C8EB1E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_C334511654972E2D53ECC72963C8F56F" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_721AE42F32CC19D73509C72963C8EB1E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_721AE42F32CC19D73509C72963C8EB1E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_C334511654972E2D53ECC72963C8F56F" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_721AE42F32CC19D73509C72963C8EB1E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ParentCompanyMember" xlink:label="loc_us-gaap_ParentCompanyMember_28C771EFE5216AEADD20C72963C8F1DF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_721AE42F32CC19D73509C72963C8EB1E" xlink:to="loc_us-gaap_ParentCompanyMember_28C771EFE5216AEADD20C72963C8F1DF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsidiaryIssuerMember" xlink:label="loc_us-gaap_SubsidiaryIssuerMember_9B47868C4FB0819C1C47C72963C8DFA4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_721AE42F32CC19D73509C72963C8EB1E" xlink:to="loc_us-gaap_SubsidiaryIssuerMember_9B47868C4FB0819C1C47C72963C8DFA4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_BADEFA1BA7668EC65C91C72963C8FEE9" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_721AE42F32CC19D73509C72963C8EB1E" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_BADEFA1BA7668EC65C91C72963C8FEE9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_30C7E072F6896A542795C72963C8E86F" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_721AE42F32CC19D73509C72963C8EB1E" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_30C7E072F6896A542795C72963C8E86F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_F623498C7FF946A5B79EC72963C8B83F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_FD9E690BD08FCB435671C72963C8E110" xlink:to="loc_us-gaap_AssetsAbstract_F623498C7FF946A5B79EC72963C8B83F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaap_AssetsCurrentAbstract_BD85426A27E50FAD26F7C72963C800EE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F623498C7FF946A5B79EC72963C8B83F" xlink:to="loc_us-gaap_AssetsCurrentAbstract_BD85426A27E50FAD26F7C72963C800EE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_F517ABAECE3ACED3DFC4C72963C8617A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_BD85426A27E50FAD26F7C72963C800EE" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_F517ABAECE3ACED3DFC4C72963C8617A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_EA3F578205DE3AB42615C72963C83143" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_BD85426A27E50FAD26F7C72963C800EE" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_EA3F578205DE3AB42615C72963C83143" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_062444562ED1CF75B3C7C72963C8A7FD" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_BD85426A27E50FAD26F7C72963C800EE" xlink:to="loc_us-gaap_InventoryNet_062444562ED1CF75B3C7C72963C8A7FD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssetsCurrent" xlink:label="loc_us-gaap_OtherAssetsCurrent_25395FEE5F93CBE45AB0C72963C9DB32" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_BD85426A27E50FAD26F7C72963C800EE" xlink:to="loc_us-gaap_OtherAssetsCurrent_25395FEE5F93CBE45AB0C72963C9DB32" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_A6B954F9B1FE9D0C9571C72963C96970" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_BD85426A27E50FAD26F7C72963C800EE" xlink:to="loc_us-gaap_AssetsCurrent_A6B954F9B1FE9D0C9571C72963C96970" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_D4CA7DCBDAF08CB246F0C72963C9C6C8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F623498C7FF946A5B79EC72963C8B83F" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_D4CA7DCBDAF08CB246F0C72963C9C6C8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_A5B4ED78E74C4C14E329C72963C9F078" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F623498C7FF946A5B79EC72963C8B83F" xlink:to="loc_us-gaap_Goodwill_A5B4ED78E74C4C14E329C72963C9F078" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_DB8764027E12D839E4D9C72963C9A8D6" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F623498C7FF946A5B79EC72963C8B83F" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_DB8764027E12D839E4D9C72963C9A8D6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredIncomeTaxAssetsNet" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_4420582DD5E5EAD179FAC72963C9A7D9" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F623498C7FF946A5B79EC72963C8B83F" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_4420582DD5E5EAD179FAC72963C9A7D9" xlink:type="arc" />
    <link:loc xlink:href="ayi-20171130.xsd#ayi_OtherLongTermAndDeferredTaxAssetsNoncurrent" xlink:label="loc_ayi_OtherLongTermAndDeferredTaxAssetsNoncurrent_7C5FB811CEF29EA02470C72963C98988" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F623498C7FF946A5B79EC72963C8B83F" xlink:to="loc_ayi_OtherLongTermAndDeferredTaxAssetsNoncurrent_7C5FB811CEF29EA02470C72963C98988" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestments" xlink:label="loc_us-gaap_EquityMethodInvestments_699F7DBFAA5701CE5B13C72963C9719C" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F623498C7FF946A5B79EC72963C8B83F" xlink:to="loc_us-gaap_EquityMethodInvestments_699F7DBFAA5701CE5B13C72963C9719C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_24935A03EEDE134FC881C72963C93169" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F623498C7FF946A5B79EC72963C8B83F" xlink:to="loc_us-gaap_Assets_24935A03EEDE134FC881C72963C93169" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C67ACD7A65AC11249DB3C72963C9FE66" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_FD9E690BD08FCB435671C72963C8E110" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C67ACD7A65AC11249DB3C72963C9FE66" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_684EBB9EC5F0010507DDC72963C97724" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C67ACD7A65AC11249DB3C72963C9FE66" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_684EBB9EC5F0010507DDC72963C97724" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_104D5DF581ED26296E98C72963C95795" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_684EBB9EC5F0010507DDC72963C97724" xlink:to="loc_us-gaap_AccountsPayableCurrent_104D5DF581ED26296E98C72963C95795" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="loc_us-gaap_LongTermDebtCurrent_0012C1EF371F240A48D0C72963C96423" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_684EBB9EC5F0010507DDC72963C97724" xlink:to="loc_us-gaap_LongTermDebtCurrent_0012C1EF371F240A48D0C72963C96423" xlink:type="arc" />
    <link:loc xlink:href="ayi-20171130.xsd#ayi_OtherAccruedAndEmployeeRelatedLiabilitiesCurrent" xlink:label="loc_ayi_OtherAccruedAndEmployeeRelatedLiabilitiesCurrent_DFF6DFD0FB34B0B892CBC72963C952B7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_684EBB9EC5F0010507DDC72963C97724" xlink:to="loc_ayi_OtherAccruedAndEmployeeRelatedLiabilitiesCurrent_DFF6DFD0FB34B0B892CBC72963C952B7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_035E38E55BD165EE4932C72963C92736" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_684EBB9EC5F0010507DDC72963C97724" xlink:to="loc_us-gaap_LiabilitiesCurrent_035E38E55BD165EE4932C72963C92736" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_6B71C45F7DD0F0E8EA28C72963C9EEC6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C67ACD7A65AC11249DB3C72963C9FE66" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_6B71C45F7DD0F0E8EA28C72963C9EEC6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_B805F9AEABA1811FBD2EC72963CA5F51" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C67ACD7A65AC11249DB3C72963C9FE66" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_B805F9AEABA1811FBD2EC72963CA5F51" xlink:type="arc" />
    <link:loc xlink:href="ayi-20171130.xsd#ayi_OtherLongTermLiabilitiesAccruedPensionAndSelfInsuranceReservesNoncurrent" xlink:label="loc_ayi_OtherLongTermLiabilitiesAccruedPensionAndSelfInsuranceReservesNoncurrent_6FFAB84485DBE789CEFBC72963CAC09A" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C67ACD7A65AC11249DB3C72963C9FE66" xlink:to="loc_ayi_OtherLongTermLiabilitiesAccruedPensionAndSelfInsuranceReservesNoncurrent_6FFAB84485DBE789CEFBC72963CAC09A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueToAffiliateNoncurrent" xlink:label="loc_us-gaap_DueToAffiliateNoncurrent_45FE886192A0C146EA32C72963CA3E21" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C67ACD7A65AC11249DB3C72963C9FE66" xlink:to="loc_us-gaap_DueToAffiliateNoncurrent_45FE886192A0C146EA32C72963CA3E21" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_62F4BC53FDD007EB61EEC72963CA6ED0" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C67ACD7A65AC11249DB3C72963C9FE66" xlink:to="loc_us-gaap_StockholdersEquity_62F4BC53FDD007EB61EEC72963CA6ED0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_502FECE0A2480A349A2DC72963CAB1A0" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C67ACD7A65AC11249DB3C72963C9FE66" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_502FECE0A2480A349A2DC72963CAB1A0" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatementsCashFlowsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedFinancialStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_50E610F41D4761DB534BC72963B0FA2C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfCondensedFinancialStatementsTable" xlink:label="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_472B8A353D111EC453E3C72963AF22D6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_50E610F41D4761DB534BC72963B0FA2C" xlink:to="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_472B8A353D111EC453E3C72963AF22D6" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_9E2F215733B69095DBBEC72963B0C6BB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_472B8A353D111EC453E3C72963AF22D6" xlink:to="loc_us-gaap_ConsolidationItemsAxis_9E2F215733B69095DBBEC72963B0C6BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_C22BD32AB1B70E2ECB2DC72963B09289_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_9E2F215733B69095DBBEC72963B0C6BB" xlink:to="loc_us-gaap_ConsolidationItemsDomain_C22BD32AB1B70E2ECB2DC72963B09289_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_C22BD32AB1B70E2ECB2DC72963B09289" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_9E2F215733B69095DBBEC72963B0C6BB" xlink:to="loc_us-gaap_ConsolidationItemsDomain_C22BD32AB1B70E2ECB2DC72963B09289" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_D385BCEC266C75C4DFFDC72963B0708C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_C22BD32AB1B70E2ECB2DC72963B09289" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_D385BCEC266C75C4DFFDC72963B0708C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_514D42A54A4A58CDD657C72963AFE97D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_472B8A353D111EC453E3C72963AF22D6" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_514D42A54A4A58CDD657C72963AFE97D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_E797FFC6685633EC1A0CC72963AFFBDE_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_514D42A54A4A58CDD657C72963AFE97D" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_E797FFC6685633EC1A0CC72963AFFBDE_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_E797FFC6685633EC1A0CC72963AFFBDE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_514D42A54A4A58CDD657C72963AFE97D" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_E797FFC6685633EC1A0CC72963AFFBDE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ParentCompanyMember" xlink:label="loc_us-gaap_ParentCompanyMember_C1B4661B82E66286A8C8C72963AF68F8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_E797FFC6685633EC1A0CC72963AFFBDE" xlink:to="loc_us-gaap_ParentCompanyMember_C1B4661B82E66286A8C8C72963AF68F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsidiaryIssuerMember" xlink:label="loc_us-gaap_SubsidiaryIssuerMember_0313B93E66B2853BCC75C72963B0A870" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_E797FFC6685633EC1A0CC72963AFFBDE" xlink:to="loc_us-gaap_SubsidiaryIssuerMember_0313B93E66B2853BCC75C72963B0A870" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_D2AC3BFCAB807B3571F3C72963B0C006" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_E797FFC6685633EC1A0CC72963AFFBDE" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_D2AC3BFCAB807B3571F3C72963B0C006" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_B3505B2B9F7A69446C27C72963B05CE2" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_E797FFC6685633EC1A0CC72963AFFBDE" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_B3505B2B9F7A69446C27C72963B05CE2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_EEA9943AE138B7FA8E98C72963B05762" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_50E610F41D4761DB534BC72963B0FA2C" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_EEA9943AE138B7FA8E98C72963B05762" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_6CACB37B793364F1A525C72963B0FB1B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_50E610F41D4761DB534BC72963B0FA2C" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_6CACB37B793364F1A525C72963B0FB1B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_2AB85E71D5510818D5AAC72963B26C82" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_6CACB37B793364F1A525C72963B0FB1B" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_2AB85E71D5510818D5AAC72963B26C82" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment" xlink:label="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_73B4ECAEDB71B605EB13C72963B22B5F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_6CACB37B793364F1A525C72963B0FB1B" xlink:to="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_73B4ECAEDB71B605EB13C72963B22B5F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromDivestitureOfBusinessesAndInterestsInAffiliates" xlink:label="loc_us-gaap_ProceedsFromDivestitureOfBusinessesAndInterestsInAffiliates_C0B8C61563ADFC4EFF0BC72963B2A840" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_6CACB37B793364F1A525C72963B0FB1B" xlink:to="loc_us-gaap_ProceedsFromDivestitureOfBusinessesAndInterestsInAffiliates_C0B8C61563ADFC4EFF0BC72963B2A840" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_2872524BE2E62C963F38C72963B245D1" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_6CACB37B793364F1A525C72963B0FB1B" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_2872524BE2E62C963F38C72963B245D1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_CABBF1D5C404A10CAF51C72963B2DFBD" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_50E610F41D4761DB534BC72963B0FA2C" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_CABBF1D5C404A10CAF51C72963B2DFBD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RepaymentsOfLongTermDebt" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_06E672D5C59EB6775C06C72963B23400" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_CABBF1D5C404A10CAF51C72963B2DFBD" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebt_06E672D5C59EB6775C06C72963B23400" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromIssuanceOfLongTermDebt" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_A448539367696469ABDEC72963B24021" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_CABBF1D5C404A10CAF51C72963B2DFBD" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_A448539367696469ABDEC72963B24021" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_696C5EB38081A357DFE1C72963B36A72" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_CABBF1D5C404A10CAF51C72963B2DFBD" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_696C5EB38081A357DFE1C72963B36A72" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_60B2FAEF852BB5B07AC6C72963B3B4CA" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_CABBF1D5C404A10CAF51C72963B2DFBD" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_60B2FAEF852BB5B07AC6C72963B3B4CA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:label="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_69A6D6E762347E867FDCC72963B33176" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_CABBF1D5C404A10CAF51C72963B2DFBD" xlink:to="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_69A6D6E762347E867FDCC72963B33176" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsOfDividendsCommonStock" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock_BD693F277982BF618A0EC72963B30912" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_CABBF1D5C404A10CAF51C72963B2DFBD" xlink:to="loc_us-gaap_PaymentsOfDividendsCommonStock_BD693F277982BF618A0EC72963B30912" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_4A1C72F5FBE66FE4A034C72963B38263" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_CABBF1D5C404A10CAF51C72963B2DFBD" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_4A1C72F5FBE66FE4A034C72963B38263" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents" xlink:label="loc_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_4DDD2C516956D4B5FB0CC72963B33C35" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_50E610F41D4761DB534BC72963B0FA2C" xlink:to="loc_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_4DDD2C516956D4B5FB0CC72963B33C35" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_B984693EE7667D0C65A8C72963B3C76D" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_50E610F41D4761DB534BC72963B0FA2C" xlink:to="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_B984693EE7667D0C65A8C72963B3C76D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_57961276ADE6822B1D4AC72963B30AD3" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_50E610F41D4761DB534BC72963B0FA2C" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_57961276ADE6822B1D4AC72963B30AD3" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatementsIncomeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedFinancialStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfCondensedFinancialStatementsTable" xlink:label="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_9A4BEE7D41AF56B5E81EC72963BD0DE2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:to="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_9A4BEE7D41AF56B5E81EC72963BD0DE2" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_187B78AC81762425EF0BC72963BE13F4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_9A4BEE7D41AF56B5E81EC72963BD0DE2" xlink:to="loc_us-gaap_ConsolidationItemsAxis_187B78AC81762425EF0BC72963BE13F4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_55C1694F3289EC2ACA5CC72963BEEB9D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_187B78AC81762425EF0BC72963BE13F4" xlink:to="loc_us-gaap_ConsolidationItemsDomain_55C1694F3289EC2ACA5CC72963BEEB9D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_55C1694F3289EC2ACA5CC72963BEEB9D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_187B78AC81762425EF0BC72963BE13F4" xlink:to="loc_us-gaap_ConsolidationItemsDomain_55C1694F3289EC2ACA5CC72963BEEB9D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_4DD3CBC07DBAB4E5B1FBC72963BE57AF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_55C1694F3289EC2ACA5CC72963BEEB9D" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_4DD3CBC07DBAB4E5B1FBC72963BE57AF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_840023A51D5250B27CBCC72963BD3CA7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_9A4BEE7D41AF56B5E81EC72963BD0DE2" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_840023A51D5250B27CBCC72963BD3CA7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_1371661BC11200394B3FC72963BE9CFD_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_840023A51D5250B27CBCC72963BD3CA7" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_1371661BC11200394B3FC72963BE9CFD_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_1371661BC11200394B3FC72963BE9CFD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_840023A51D5250B27CBCC72963BD3CA7" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_1371661BC11200394B3FC72963BE9CFD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ParentCompanyMember" xlink:label="loc_us-gaap_ParentCompanyMember_C2FDCCAF5A5CF8E2A733C72963BEBB1A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_1371661BC11200394B3FC72963BE9CFD" xlink:to="loc_us-gaap_ParentCompanyMember_C2FDCCAF5A5CF8E2A733C72963BEBB1A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsidiaryIssuerMember" xlink:label="loc_us-gaap_SubsidiaryIssuerMember_EC68056C46280A259822C72963BEB4CA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_1371661BC11200394B3FC72963BE9CFD" xlink:to="loc_us-gaap_SubsidiaryIssuerMember_EC68056C46280A259822C72963BEB4CA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_A2484E77FDA454D20D76C72963BEC1A8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_1371661BC11200394B3FC72963BE9CFD" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_A2484E77FDA454D20D76C72963BEC1A8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_97C0A69CE8B7BA489685C72963BE3E80" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_1371661BC11200394B3FC72963BE9CFD" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_97C0A69CE8B7BA489685C72963BE3E80" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SalesRevenueGoodsNetAbstract" xlink:label="loc_us-gaap_SalesRevenueGoodsNetAbstract_A732EA4389D858717438C72963BE905A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:to="loc_us-gaap_SalesRevenueGoodsNetAbstract_A732EA4389D858717438C72963BE905A" xlink:type="arc" />
    <link:loc xlink:href="ayi-20171130.xsd#ayi_SalesRevenueGoodsExternal" xlink:label="loc_ayi_SalesRevenueGoodsExternal_3958799E01E0D6590CC4C72963BEFCB4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesRevenueGoodsNetAbstract_A732EA4389D858717438C72963BE905A" xlink:to="loc_ayi_SalesRevenueGoodsExternal_3958799E01E0D6590CC4C72963BEFCB4" xlink:type="arc" />
    <link:loc xlink:href="ayi-20171130.xsd#ayi_SalesRevenueGoodsIntercompany" xlink:label="loc_ayi_SalesRevenueGoodsIntercompany_65D7D61A19CEBB7AEC1CC72963BE36F9" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesRevenueGoodsNetAbstract_A732EA4389D858717438C72963BE905A" xlink:to="loc_ayi_SalesRevenueGoodsIntercompany_65D7D61A19CEBB7AEC1CC72963BE36F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SalesRevenueGoodsNet" xlink:label="loc_us-gaap_SalesRevenueGoodsNet_838901B92F296ECD8EF2C72963BE236E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesRevenueGoodsNetAbstract_A732EA4389D858717438C72963BE905A" xlink:to="loc_us-gaap_SalesRevenueGoodsNet_838901B92F296ECD8EF2C72963BE236E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostOfGoodsSold" xlink:label="loc_us-gaap_CostOfGoodsSold_E61A5D120CD24C30F4A6C72963BFCBFC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:to="loc_us-gaap_CostOfGoodsSold_E61A5D120CD24C30F4A6C72963BFCBFC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_597FC96A94FBB0251792C72963BF57EC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:to="loc_us-gaap_GrossProfit_597FC96A94FBB0251792C72963BF57EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_F3FF819D8D73716D74FCC72963BF4E19" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_F3FF819D8D73716D74FCC72963BF4E19" xlink:type="arc" />
    <link:loc xlink:href="ayi-20171130.xsd#ayi_IntercompanyCharges" xlink:label="loc_ayi_IntercompanyCharges_B7964D616DFB0283A509C72963BFF887" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:to="loc_ayi_IntercompanyCharges_B7964D616DFB0283A509C72963BFF887" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCharges" xlink:label="loc_us-gaap_RestructuringCharges_84AC730325715D0C9733C72963BF5AD9" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:to="loc_us-gaap_RestructuringCharges_84AC730325715D0C9733C72963BF5AD9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_036BDD60E856D0A9474BC72963BFDD6A" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:to="loc_us-gaap_OperatingIncomeLoss_036BDD60E856D0A9474BC72963BFDD6A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestRevenueExpenseNet" xlink:label="loc_us-gaap_InterestRevenueExpenseNet_CA822AD7E6222AB88AAFC72963BFA4FC" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:to="loc_us-gaap_InterestRevenueExpenseNet_CA822AD7E6222AB88AAFC72963BFA4FC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TemporaryEquityInterestInSubsidiaryEarnings" xlink:label="loc_us-gaap_TemporaryEquityInterestInSubsidiaryEarnings_F824CAE68AA215F8B258C72963BFF078" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:to="loc_us-gaap_TemporaryEquityInterestInSubsidiaryEarnings_F824CAE68AA215F8B258C72963BFF078" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_DBBF46B9CE7AA1BB1DCCC72963BF4289" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_DBBF46B9CE7AA1BB1DCCC72963BF4289" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_3F1E3354E66D2DEF56C5C72963BFADB1" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_3F1E3354E66D2DEF56C5C72963BFADB1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_31EB60B0EB9875899D70C72963BF9DB0" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_31EB60B0EB9875899D70C72963BF9DB0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_A8501FEEEF1BB19A720AC72963BFFFB9" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:to="loc_us-gaap_NetIncomeLoss_A8501FEEEF1BB19A720AC72963BFFFB9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParentAbstract" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParentAbstract_D248AF49619D95A9C525C72963BFABCB" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParentAbstract_D248AF49619D95A9C525C72963BFABCB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_B2672C3DA101F8C3E098C72963BF5321" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParentAbstract_D248AF49619D95A9C525C72963BFABCB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_B2672C3DA101F8C3E098C72963BF5321" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent_54EFB717172D2D855669C72963BF3A10" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParentAbstract_D248AF49619D95A9C525C72963BFABCB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent_54EFB717172D2D855669C72963BF3A10" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_40D0118E660355AA7D78C72963BFDFFE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParentAbstract_D248AF49619D95A9C525C72963BFABCB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_40D0118E660355AA7D78C72963BFDFFE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_008366AA754B803D7F7EC72963BF3718" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_23B763B973934B380761C72963BE2B20" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_008366AA754B803D7F7EC72963BF3718" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatementsTables" xlink:type="extended" />
</link:linkbase>
