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<!-- Creation Date :2023-05-08T14:37:12.3918+00:00 -->
<!-- Copyright (c) 2023 Donnelly Financial Solutions, Inc. All Rights Reserved. -->
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  <xsd:element id="ajg_BusinessAcquisitionCostOfAcquiredEntityPurchasePriceNet" name="BusinessAcquisitionCostOfAcquiredEntityPurchasePriceNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_BusinessAcquisitionPurchasePriceAllocationGoodwillNotExpectedTaxDeductibleAmount" name="BusinessAcquisitionPurchasePriceAllocationGoodwillNotExpectedTaxDeductibleAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_BusinessAcquisitionsProFormaNetIncomeLossToControllingInterest" name="BusinessAcquisitionsProFormaNetIncomeLossToControllingInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_BusinessAcquisitionsPurchasePriceAllocationGoodwillAmount" name="BusinessAcquisitionsPurchasePriceAllocationGoodwillAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_BusinessCombinationAggregateEarnoutObligationExpectedSettlementInCash" name="BusinessCombinationAggregateEarnoutObligationExpectedSettlementInCash" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_BusinessCombinationAggregateEarnoutObligationExpectedSettlementInCashOrStockAtOption" name="BusinessCombinationAggregateEarnoutObligationExpectedSettlementInCashOrStockAtOption" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_BusinessCombinationAggregateEarnoutObligationMaximum" name="BusinessCombinationAggregateEarnoutObligationMaximum" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_BusinessCombinationAggregateEarnoutObligationRecordedMaximum" name="BusinessCombinationAggregateEarnoutObligationRecordedMaximum" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_BusinessCombinationAnnualizeRevenue" name="BusinessCombinationAnnualizeRevenue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_BusinessCombinationConsiderationToSellerFundedExpensesAndNetWorkingCapital" name="BusinessCombinationConsiderationToSellerFundedExpensesAndNetWorkingCapital" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_BusinessCombinationPeriodOfExistence" name="BusinessCombinationPeriodOfExistence" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAccruedLiability" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAccruedLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalentsAndRestrictedCash" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalentsAndRestrictedCash" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFiduciaryAssetsCurrent" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFiduciaryAssetsCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFiduciaryLiabilitiesCurrent" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFiduciaryLiabilitiesCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_CashAndEquityAwardWithAggregateFairValueVestedAndDistributedToParticipants" name="CashAndEquityAwardWithAggregateFairValueVestedAndDistributedToParticipants" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_CashBasedCompensationAwardExpenses" name="CashBasedCompensationAwardExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_CashCashEquivalentsRestrictedCashAndFiduciaryCash" name="CashCashEquivalentsRestrictedCashAndFiduciaryCash" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_ChangeInEstimatedAcquisitionEarnoutPayables" name="ChangeInEstimatedAcquisitionEarnoutPayables" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_CompensationApprovedByCommitteeValue" name="CompensationApprovedByCommitteeValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_ContractWithCustomerImpactOfChangeInForeignExchangeRates" name="ContractWithCustomerImpactOfChangeInForeignExchangeRates" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_ContractWithCustomerLiabilityAdditions" name="ContractWithCustomerLiabilityAdditions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_CostReimbursements" name="CostReimbursements" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_DebtInstrumentMaturityYear" name="DebtInstrumentMaturityYear" type="xbrli:gYearItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_DebtLongTermAndShortTermCombinedAmountGross" name="DebtLongTermAndShortTermCombinedAmountGross" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_DeferredEquityParticipationPlanDistributionsToKeyExecutivesAge" name="DeferredEquityParticipationPlanDistributionsToKeyExecutivesAge" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_DeferredEquityParticipationSubPlanDistributionsRequisiteServiceDescription" name="DeferredEquityParticipationSubPlanDistributionsRequisiteServiceDescription" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_DeferredEquityParticipationSubPlanDistributionsToKeyExecutivesAge" name="DeferredEquityParticipationSubPlanDistributionsToKeyExecutivesAge" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_DefinedBenefitPlanPercentageOfEligibleCompensationForMatchingContributionsByEmployer" name="DefinedBenefitPlanPercentageOfEligibleCompensationForMatchingContributionsByEmployer" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_DerivativeInterestRateContractsHedgesSettled" name="DerivativeInterestRateContractsHedgesSettled" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_EarnoutPaymentsForAcquisitions" name="EarnoutPaymentsForAcquisitions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_ExercisePriceOfStockOptionsPercentOfFairMarketValueOfShareOfCommonStockOnDateOfGrant" name="ExercisePriceOfStockOptionsPercentOfFairMarketValueOfShareOfCommonStockOnDateOfGrant" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_ExpirationLists" name="ExpirationLists" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_FairValueInputsAttritionRate" name="FairValueInputsAttritionRate" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_FiduciaryAssetsCurrent" name="FiduciaryAssetsCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_FiduciaryCash" name="FiduciaryCash" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_FiduciaryLiabilitiesCurrent" name="FiduciaryLiabilitiesCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFour" name="FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFour" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_GainsLossesOnExtinguishmentOfDebtRelatedToOperatingActivities" name="GainsLossesOnExtinguishmentOfDebtRelatedToOperatingActivities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_IncreaseDecreaseInPremiumsAndFeeReceivable" name="IncreaseDecreaseInPremiumsAndFeeReceivable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_LiabilitiesRecordedOnSelfInsurance" name="LiabilitiesRecordedOnSelfInsurance" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_MatchingContributionsVestingSchedule" name="MatchingContributionsVestingSchedule" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_MaximumPotentialEarnoutPayable" name="MaximumPotentialEarnoutPayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_MinorityInterestIncreaseDecreaseFromRedemptions" name="MinorityInterestIncreaseDecreaseFromRedemptions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_NetBorrowingsPaymentsOnPremiumFinancingDebtFacility" name="NetBorrowingsPaymentsOnPremiumFinancingDebtFacility" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_NetChangeInAccruedCompensationAndOtherAccruedLiabilities" name="NetChangeInAccruedCompensationAndOtherAccruedLiabilities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_NetChangeInCollectedBillingsAndDepositsReceivedFromCustomers" name="NetChangeInCollectedBillingsAndDepositsReceivedFromCustomers" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_NetChangeInFiduciaryAssetsAndLiabilities" name="NetChangeInFiduciaryAssetsAndLiabilities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_NetProceedsFromSalesOfOperations" name="NetProceedsFromSalesOfOperations" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_NumberOfCommercialCleanCoalProductionFacilities" name="NumberOfCommercialCleanCoalProductionFacilities" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="ajg_NumberOfCountriesInWhichCompanyDoesBusinessThroughNetworkOfCorrespondentBrokersAndConsultants" name="NumberOfCountriesInWhichCompanyDoesBusinessThroughNetworkOfCorrespondentBrokersAndConsultants" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_NumberOfCredentialedActuaries" name="NumberOfCredentialedActuaries" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_NumberOfEmployees" name="NumberOfEmployees" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_NumberOfLetterOfCreditIssued" name="NumberOfLetterOfCreditIssued" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="ajg_NumberOfPeriodsOptionsExpire" name="NumberOfPeriodsOptionsExpire" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_NumberOfSquareFeet" name="NumberOfSquareFeet" type="dtr-types:areaItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="ajg_PaymentsForProceedsFromSettlementsOfTerminatedInterestRateSwaps" name="PaymentsForProceedsFromSettlementsOfTerminatedInterestRateSwaps" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_PaymentsToAcquireBusinessesNetOfCashAndRestrictedCashAcquired" name="PaymentsToAcquireBusinessesNetOfCashAndRestrictedCashAcquired" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_PeriodForOptionsToExpireFromDateOfGrant" name="PeriodForOptionsToExpireFromDateOfGrant" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_PeriodOfServiceFromGrantDateStockOptionsAwardedNotSubjectToForfeiture" name="PeriodOfServiceFromGrantDateStockOptionsAwardedNotSubjectToForfeiture" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_PremiumFinancingBorrowings" name="PremiumFinancingBorrowings" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_PremiumsPayableToUnderwritingEnterprises" name="PremiumsPayableToUnderwritingEnterprises" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_ProceedsFromFiduciaryAssetsAndLiabilities" name="ProceedsFromFiduciaryAssetsAndLiabilities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_ProceedsFromRepaymentsOfCorporateRelatedLongTermDebt" name="ProceedsFromRepaymentsOfCorporateRelatedLongTermDebt" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_ProceedsFromSubPlan" name="ProceedsFromSubPlan" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_ProvisionalCompensationCashAwardApprovedForFutureGrantByCompensationCommitteeUnits" name="ProvisionalCompensationCashAwardApprovedForFutureGrantByCompensationCommitteeUnits" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="ajg_ProvisionalCompensationCashAwardApprovedForFutureGrantByCompensationCommitteeValue" name="ProvisionalCompensationCashAwardApprovedForFutureGrantByCompensationCommitteeValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_ProvisionalCompensationCashAwardWithAggregateFairValueVestedAndDistributedToParticipants" name="ProvisionalCompensationCashAwardWithAggregateFairValueVestedAndDistributedToParticipants" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_RecordedEarnOutPayable" name="RecordedEarnOutPayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_RecordedUnconditionalPurchaseObligationDueAfterFourthYear" name="RecordedUnconditionalPurchaseObligationDueAfterFourthYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_RecordedUnconditionalPurchaseObligationReceivable" name="RecordedUnconditionalPurchaseObligationReceivable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_RecordedUnconditionalPurchaseObligationReceivableAfterFourthYear" name="RecordedUnconditionalPurchaseObligationReceivableAfterFourthYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_RecordedUnconditionalPurchaseObligationReceivableInFourthYear" name="RecordedUnconditionalPurchaseObligationReceivableInFourthYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_RecordedUnconditionalPurchaseObligationReceivableInRemainderOfFiscalYear" name="RecordedUnconditionalPurchaseObligationReceivableInRemainderOfFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_RecordedUnconditionalPurchaseObligationReceivableInSecondYear" name="RecordedUnconditionalPurchaseObligationReceivableInSecondYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_RecordedUnconditionalPurchaseObligationReceivableInThirdYear" name="RecordedUnconditionalPurchaseObligationReceivableInThirdYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_RecordedUnconditionalPurchaseObligationReceivableWithinOneYear" name="RecordedUnconditionalPurchaseObligationReceivableWithinOneYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_RevenueFromContractWithCustomerBeforeReimbursementsExcludingAssessedTax" name="RevenueFromContractWithCustomerBeforeReimbursementsExcludingAssessedTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_RevenueFromContractWithCustomerExcludingAssessedTaxReimbursements" name="RevenueFromContractWithCustomerExcludingAssessedTaxReimbursements" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardAggregateFairValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAggregateFairValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingDate" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingDate" type="xbrli:dateItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodFairValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodFairValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsSharePool" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsSharePool" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsSharesAgainstPool" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsSharesAgainstPool" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedInPeriodIntrinsicValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedInPeriodIntrinsicValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePercentageYearOne" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePercentageYearOne" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePercentageYearThree" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePercentageYearThree" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePercentageYearTwo" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePercentageYearTwo" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedAndExpectedToVestExercisableWeightedAverageExercisePrice" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedAndExpectedToVestExercisableWeightedAverageExercisePrice" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonVestedAndExpectedToVestNumberOfShares" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonVestedAndExpectedToVestNumberOfShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="ajg_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingAggregateIntrinsicValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingAggregateIntrinsicValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_SharebasedCompensationArrangementNonVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" name="SharebasedCompensationArrangementNonVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_StockIssuedDuringPeriodSharesDeferredCompensationAndRestrictedStock" name="StockIssuedDuringPeriodSharesDeferredCompensationAndRestrictedStock" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_StockIssuedDuringPeriodValueDeferredCompensationAndRestrictedStockExpenseBenefit" name="StockIssuedDuringPeriodValueDeferredCompensationAndRestrictedStockExpenseBenefit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="ajg_UltimateAwardValueMultiplesOfOriginalValueOfUnitsMaximum" name="UltimateAwardValueMultiplesOfOriginalValueOfUnitsMaximum" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_UltimateAwardValueMultiplesOfOriginalValueOfUnitsMinimum" name="UltimateAwardValueMultiplesOfOriginalValueOfUnitsMinimum" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_UnearnedDeferredCompensationShare" name="UnearnedDeferredCompensationShare" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_UnearnedDeferredCompensationValue" name="UnearnedDeferredCompensationValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="ajg_WeightedAverageNumberOfCommonAndCommonEquivalentSharesOutstanding" name="WeightedAverageNumberOfCommonAndCommonEquivalentSharesOutstanding" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_WeightedAveragePeriod" name="WeightedAveragePeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_BusinessAcquisitionActualRevenueAndPreTaxIncomeLossLineItems" name="BusinessAcquisitionActualRevenueAndPreTaxIncomeLossLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_CommitmentsContingenciesAndOffBalanceSheetArrangementsLineItems" name="CommitmentsContingenciesAndOffBalanceSheetArrangementsLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_CommonStockOptionsRestrictedStockWarrantsAndChangesInCapitalizationLineItems" name="CommonStockOptionsRestrictedStockWarrantsAndChangesInCapitalizationLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_InvestmentsAndEmployeeDeferredCompensationPlanLineItems" name="InvestmentsAndEmployeeDeferredCompensationPlanLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_StockOptionPlansLineItems" name="StockOptionPlansLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_AccruedCompensationAndOtherCurrentLiabilitiesMember" name="AccruedCompensationAndOtherCurrentLiabilitiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_AUDDenominatedTrancheMember" name="AUDDenominatedTrancheMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_BchrHoldingsLPMember" name="BchrHoldingsLPMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_BlackScholesOptionPricingModelMember" name="BlackScholesOptionPricingModelMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_BrokerageSegmentMember" name="BrokerageSegmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_BrokerFeesMember" name="BrokerFeesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_BusinessAcquisitionMember" name="BusinessAcquisitionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_CashAwardsMember" name="CashAwardsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_CommissionRevenueMember" name="CommissionRevenueMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_CommissionsMember" name="CommissionsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_ContingentRevenueMember" name="ContingentRevenueMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_ContractualObligationsMember" name="ContractualObligationsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_CreditAgreementMember" name="CreditAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_DebtObligationMember" name="DebtObligationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_DeferredCashParticipationPlanMember" name="DeferredCashParticipationPlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_DeferredEquityParticipationPlanMember" name="DeferredEquityParticipationPlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_DeferredEquityParticipationPlanSubPlansMember" name="DeferredEquityParticipationPlanSubPlansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_DevittInsuranceServicesLimitedMember" name="DevittInsuranceServicesLimitedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_EighteenOtherAcquisitionsMember" name="EighteenOtherAcquisitionsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_ErrorsAndOmissionsMember" name="ErrorsAndOmissionsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_ExpirationListsMember" name="ExpirationListsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FacilityBMember" name="FacilityBMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FacilityCAndFacilityDMember" name="FacilityCAndFacilityDMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FirstIrelandRiskManagementLtdMember" name="FirstIrelandRiskManagementLtdMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFivePointFiveZeroPercentBalloonDueMarchTwoTwoThousandThirtyThreeMember" name="FixedRateOfFivePointFiveZeroPercentBalloonDueMarchTwoTwoThousandThirtyThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFivePointFiveZeroPercentBalloonDueMayTwoTwoThousandThirtyThreeMember" name="FixedRateOfFivePointFiveZeroPercentBalloonDueMayTwoTwoThousandThirtyThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFivePointFourFivePercentBalloonDueMarchThirteenTwoThousandThirtyNineMember" name="FixedRateOfFivePointFourFivePercentBalloonDueMarchThirteenTwoThousandThirtyNineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFivePointFourNinePercentBalloonDueFebruaryTenTwoThousandTwentyThreeMember" name="FixedRateOfFivePointFourNinePercentBalloonDueFebruaryTenTwoThousandTwentyThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFivePointOneFourPercentBalloonDueMarchThirteenTwoThousandThirtyOneMember" name="FixedRateOfFivePointOneFourPercentBalloonDueMarchThirteenTwoThousandThirtyOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFivePointSevenFivePercentBalloonDueMarchTwoTwoThousandFiftyThreeMember" name="FixedRateOfFivePointSevenFivePercentBalloonDueMarchTwoTwoThousandFiftyThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFivePointTwoNinePercentBalloonDueMarchThirteenTwoThousandThirtyFourMember" name="FixedRateOfFivePointTwoNinePercentBalloonDueMarchThirteenTwoThousandThirtyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointFiveEightPercentBalloonDueFebruaryTwentySevenTwoThousandTwentyFourMember" name="FixedRateOfFourPointFiveEightPercentBalloonDueFebruaryTwentySevenTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointFiveFivePercentBalloonDueJuneTwoTwoThousandTwentyEightMember" name="FixedRateOfFourPointFiveFivePercentBalloonDueJuneTwoTwoThousandTwentyEightMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointFiveNinePercentBalloonDueJuneThirteenTwoThousandThirtyThreeMember" name="FixedRateOfFourPointFiveNinePercentBalloonDueJuneThirteenTwoThousandThirtyThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointFourFourPercentBalloonDueJuneThirteenTwoThousandThirtyMember" name="FixedRateOfFourPointFourFourPercentBalloonDueJuneThirteenTwoThousandThirtyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointFourNinePercentBalloonDueJanuaryThirtyTwoThousandFortyMember" name="FixedRateOfFourPointFourNinePercentBalloonDueJanuaryThirtyTwoThousandFortyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointFourZeroPercentBalloonDueJuneTwoTwoThousandTwentySixMember" name="FixedRateOfFourPointFourZeroPercentBalloonDueJuneTwoTwoThousandTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointNineEightPercentBalloonDueFebruaryTwentySevenTwoThousandTwentyNineMember" name="FixedRateOfFourPointNineEightPercentBalloonDueFebruaryTwentySevenTwoThousandTwentyNineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointOneFourPercentBalloonDueAugustFourTwoThousandTwentySevenMember" name="FixedRateOfFourPointOneFourPercentBalloonDueAugustFourTwoThousandTwentySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointOneNinePercentBalloonDueAugustTwoTwoThousandTwentyNineMember" name="FixedRateOfFourPointOneNinePercentBalloonDueAugustTwoTwoThousandTwentyNineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointOneNinePercentBalloonDueJuneTwentySevenTwoThousandTwentyNineMember" name="FixedRateOfFourPointOneNinePercentBalloonDueJuneTwentySevenTwoThousandTwentyNineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointOneThreePercentageBalloonDueJuneTwentyFourTwoThousandTwentyThreeMember" name="FixedRateOfFourPointOneThreePercentageBalloonDueJuneTwentyFourTwoThousandTwentyThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointSevenThreePercentBalloonDueFebruaryTwentySevenTwoThousandTwentySixMember" name="FixedRateOfFourPointSevenThreePercentBalloonDueFebruaryTwentySevenTwoThousandTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointSevenTwoPercentBalloonDueFebruaryThirteenTwoThousandTwentyFourMember" name="FixedRateOfFourPointSevenTwoPercentBalloonDueFebruaryThirteenTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointSevenZeroPercentBalloonDueJuneTwoTwoThousandThirtyOneMember" name="FixedRateOfFourPointSevenZeroPercentBalloonDueJuneTwoTwoThousandThirtyOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointSixNinePercentBalloonDueJuneThirteenTwoThousandThirtyEightMember" name="FixedRateOfFourPointSixNinePercentBalloonDueJuneThirteenTwoThousandThirtyEightMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointThreeFourPercentBalloonDueAugustTwoTwoThousandThirtyTwoMember" name="FixedRateOfFourPointThreeFourPercentBalloonDueAugustTwoTwoThousandThirtyTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointThreeFourPercentBalloonDueJuneThirteenTwoThousandTwentyEightMember" name="FixedRateOfFourPointThreeFourPercentBalloonDueJuneThirteenTwoThousandTwentyEightMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointThreeFourPercentBalloonDueJuneTwentySevenTwoThousandThirtyTwoMember" name="FixedRateOfFourPointThreeFourPercentBalloonDueJuneTwentySevenTwoThousandThirtyTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointThreeOnePercentBalloonDueJuneTwentyFourTwoThousandTwentyFiveMember" name="FixedRateOfFourPointThreeOnePercentBalloonDueJuneTwentyFourTwoThousandTwentyFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointThreeSixPercentBalloonDueJuneTwentyFourTwoThousandTwentySixMember" name="FixedRateOfFourPointThreeSixPercentBalloonDueJuneTwentyFourTwoThousandTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointTwoFourPercentBalloonDueJanuaryThirtyTwoThousandThirtyFiveMember" name="FixedRateOfFourPointTwoFourPercentBalloonDueJanuaryThirtyTwoThousandThirtyFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointZeroNinePercentBalloonDueAugustTwoTwoThousandTwentySevenMember" name="FixedRateOfFourPointZeroNinePercentBalloonDueAugustTwoTwoThousandTwentySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointZeroNinePercentBalloonDueJanuaryThirtyTwoThousandThirtyTwoMember" name="FixedRateOfFourPointZeroNinePercentBalloonDueJanuaryThirtyTwoThousandThirtyTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfFourPointZeroNinePercentBalloonDueJuneTwentySevenTwoThousandTwentySevenMember" name="FixedRateOfFourPointZeroNinePercentBalloonDueJuneTwentySevenTwoThousandTwentySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfThreePointFiveZeroPercentBalloonDueMayTwentyTwoThousandFiftyOneMember" name="FixedRateOfThreePointFiveZeroPercentBalloonDueMayTwentyTwoThousandFiftyOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfThreePointFourEightPercentBalloonDueDecemberTwoTwothousandTwentyNineMember" name="FixedRateOfThreePointFourEightPercentBalloonDueDecemberTwoTwothousandTwentyNineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfThreePointFourSixPercentageBalloonDueDecemberOneTwoThousandTwentySevenMember" name="FixedRateOfThreePointFourSixPercentageBalloonDueDecemberOneTwoThousandTwentySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfThreePointNineNinePercentBalloonDueJanuaryThirtyTwoThousandThirtyMember" name="FixedRateOfThreePointNineNinePercentBalloonDueJanuaryThirtyTwoThousandThirtyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfThreePointSevenFivePercentBalloonDueJanuaryThirtyTwoThousandTwentySevenMember" name="FixedRateOfThreePointSevenFivePercentBalloonDueJanuaryThirtyTwoThousandTwentySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfThreePointSixNinePercentBalloonDueJuneFourteenTwoThousandTwentyTwoMember" name="FixedRateOfThreePointSixNinePercentBalloonDueJuneFourteenTwoThousandTwentyTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfThreePointZeroFivePercentBalloonDueMarchNineTwoThousandFiftyTwoMember" name="FixedRateOfThreePointZeroFivePercentBalloonDueMarchNineTwoThousandFiftyTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfTwoPointFourFourPercentBalloonDueFebruaryTenTwoThousandThirtySixMember" name="FixedRateOfTwoPointFourFourPercentBalloonDueFebruaryTenTwoThousandThirtySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfTwoPointFourSixPercentBalloonDueMayFiveTwoThousandThirtySixMember" name="FixedRateOfTwoPointFourSixPercentBalloonDueMayFiveTwoThousandThirtySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRateOfTwoPointFourZeroPercentBalloonDueNovemberNineTwoThousandThirtyOneMember" name="FixedRateOfTwoPointFourZeroPercentBalloonDueNovemberNineTwoThousandThirtyOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRatesOfFivePointZeroFourPercentageBalloonDueFebruaryThirteenTwoThousandTwentyNineMember" name="FixedRatesOfFivePointZeroFourPercentageBalloonDueFebruaryThirteenTwoThousandTwentyNineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRatesOfFourPointEightFivePercentBalloonDueFebruaryThirteenTwoThousandTwentySixMember" name="FixedRatesOfFourPointEightFivePercentBalloonDueFebruaryThirteenTwoThousandTwentySixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FixedRatesOfFourPointFourEightPercentBalloonDueJuneTwelveTwoThousandThirtyFourMember" name="FixedRatesOfFourPointFourEightPercentBalloonDueJuneTwelveTwoThousandThirtyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_FloatingInterestRateOfOnePointFourZeroPercentLIBORPlusBalloonDueJuneThirteenTwoThousandTwentyFourMember" name="FloatingInterestRateOfOnePointFourZeroPercentLIBORPlusBalloonDueJuneThirteenTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_GainsOnDivestituresMember" name="GainsOnDivestituresMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_GallagherReMember" name="GallagherReMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_IghMember" name="IghMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_InnovuGroupHoldingCompanyLimitedMember" name="InnovuGroupHoldingCompanyLimitedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_InsuranceBrokerageAndRiskManagementServicesMember" name="InsuranceBrokerageAndRiskManagementServicesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_InsuranceBrokerageManagementServicesMember" name="InsuranceBrokerageManagementServicesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_InterbankRatePlusOnePointEightFiveZeroPercentExpiresSeptemberFifteenTwoThousandTwentyFourMember" name="InterbankRatePlusOnePointEightFiveZeroPercentExpiresSeptemberFifteenTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_InterbankRatePlusOnePointFiveZeroZeroPercentExpiresSeptemberFifteenTwoThousandTwentyFourMember" name="InterbankRatePlusOnePointFiveZeroZeroPercentExpiresSeptemberFifteenTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_InterbankRatePlusZeroPointEightThreeZeroPercentExpiresSeptemberFifteenTwoThousandTwentyFourMember" name="InterbankRatePlusZeroPointEightThreeZeroPercentExpiresSeptemberFifteenTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_InterbankRatePlusZeroPointNineNineZeroPercentExpiresSeptemberFifteenTwoThousandTwentyFourMember" name="InterbankRatePlusZeroPointNineNineZeroPercentExpiresSeptemberFifteenTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_InterbankRatesExpiresSeptemberFifteenTwoThousandTwentyThreeMember" name="InterbankRatesExpiresSeptemberFifteenTwoThousandTwentyThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_InterestOnDebtMember" name="InterestOnDebtMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_InterestRateContractsHedgesMember" name="InterestRateContractsHedgesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_LaborAndRelatedExpenseMember" name="LaborAndRelatedExpenseMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_LettersOfCreditMember" name="LettersOfCreditMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_LongTermIncentivePlanMember" name="LongTermIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_MAndTInsuranceAgencyMember" name="MAndTInsuranceAgencyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_MTinsuranceagencyincMember" name="MTinsuranceagencyincMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_NetGainsOnDivestituresMember" name="NetGainsOnDivestituresMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_NineOtherAcquisitionsMember" name="NineOtherAcquisitionsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_NotePurchaseAgreementMember" name="NotePurchaseAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_NzdDenominatedTrancheMember" name="NzdDenominatedTrancheMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_OperatingLeaseObligationMember" name="OperatingLeaseObligationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_OtherForeignMember" name="OtherForeignMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_OutstandingPurchaseObligationsMember" name="OutstandingPurchaseObligationsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_PremiumFinancingDebtFacilityMember" name="PremiumFinancingDebtFacilityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_PrimeOrLiborPlusUpToOnePointFourFivePercentExpiresJuneSevenTwoThousandTwentyFourMember" name="PrimeOrLiborPlusUpToOnePointFourFivePercentExpiresJuneSevenTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_PrimeOrSofrPlusUpToOnePointFourZeroPercentExpiresJuneSevenTwoThousandTwentyFourMember" name="PrimeOrSofrPlusUpToOnePointFourZeroPercentExpiresJuneSevenTwoThousandTwentyFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_QualifiedContributorySavingsAndThriftFourZeroOneKPlanMember" name="QualifiedContributorySavingsAndThriftFourZeroOneKPlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_Range01Member" name="Range01Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_Range02Member" name="Range02Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_Range03Member" name="Range03Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_Range04Member" name="Range04Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_Range05Member" name="Range05Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_Range06Member" name="Range06Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_Range07Member" name="Range07Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_Range08Member" name="Range08Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_RentCaptiveFacilityMember" name="RentCaptiveFacilityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_RiskManagementSegmentMember" name="RiskManagementSegmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_SecurityDepositMember" name="SecurityDepositMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_SelfInsuranceDeductiblesMember" name="SelfInsuranceDeductiblesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_SeniorUnsecuredNoteMember" name="SeniorUnsecuredNoteMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_SubleaseArrangementsMember" name="SubleaseArrangementsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_SupplementalRevenueMember" name="SupplementalRevenueMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_SupplementalRevenueMemberMember" name="SupplementalRevenueMemberMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_TenYearNotesMember" name="TenYearNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_ThirtyYearNotesMember" name="ThirtyYearNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_ThirtyYearSeniorNotesMember" name="ThirtyYearSeniorNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_TwoThousandEighteenProvisionalCashAwardsMember" name="TwoThousandEighteenProvisionalCashAwardsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_TwoThousandNineteenProvisionalCashAwardsMember" name="TwoThousandNineteenProvisionalCashAwardsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_TwoThousandSeventeenLongTermincentivePlanMember" name="TwoThousandSeventeenLongTermincentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_TwoThousandSeventeenPerformanceShareAwardsMember" name="TwoThousandSeventeenPerformanceShareAwardsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_TwoThousandTwentyOneAcquisitionsMember" name="TwoThousandTwentyOneAcquisitionsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_TwoThousandTwentyOneProvisionalCashAwardsMember" name="TwoThousandTwentyOneProvisionalCashAwardsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_TwoThousandTwentyProvisionalCashAwardsMember" name="TwoThousandTwentyProvisionalCashAwardsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_TwoThousandTwentyThreeAcquisitionsMember" name="TwoThousandTwentyThreeAcquisitionsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_TwoThousandTwentyThreeProvisionalCashAwardsMember" name="TwoThousandTwentyThreeProvisionalCashAwardsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_TwoThousandTwentyTwoAcquisitionsMember" name="TwoThousandTwentyTwoAcquisitionsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_TwoThousandTwentyTwoProvisionalCashAwardsMember" name="TwoThousandTwentyTwoProvisionalCashAwardsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_UnconsolidatedInvestmentsInEnterprisesMember" name="UnconsolidatedInvestmentsInEnterprisesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_UnsecuredMulticurrencyCreditAgreementMember" name="UnsecuredMulticurrencyCreditAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_UnvestedRestrictedStockMember" name="UnvestedRestrictedStockMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_UpToFourPointFiveMillionMember" name="UpToFourPointFiveMillionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_UpToTenMillionMember" name="UpToTenMillionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_UpToTwentyPointZeroMillionMember" name="UpToTwentyPointZeroMillionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_UpToTwentySevenPointZeroMillionMember" name="UpToTwentySevenPointZeroMillionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_WillisTowersWatsonPLCMember" name="WillisTowersWatsonPLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_AnnualActivityOfStockOptionPlansTable" name="AnnualActivityOfStockOptionPlansTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_BusinessAcquisitionActualRevenueAndPreTaxIncomeLossTable" name="BusinessAcquisitionActualRevenueAndPreTaxIncomeLossTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_CommitmentsContingenciesAndOffBalanceSheetArrangementsTable" name="CommitmentsContingenciesAndOffBalanceSheetArrangementsTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_CommonStockOptionsRestrictedStockWarrantsAndChangesInCapitalizationTable" name="CommonStockOptionsRestrictedStockWarrantsAndChangesInCapitalizationTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_InvestmentsAndEmployeeDeferredCompensationPlanTable" name="InvestmentsAndEmployeeDeferredCompensationPlanTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="ajg_CarryingAmountOfGoodwillAllocatedByDomesticAndForeignOperationsTableTextBlock" name="CarryingAmountOfGoodwillAllocatedByDomesticAndForeignOperationsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_ChangeInPresentationOfFiduciaryAssetsAndLiabilitiesPolicyTextBlock" name="ChangeInPresentationOfFiduciaryAssetsAndLiabilitiesPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_ContractWithCustomerLiabilityTableTextBlock" name="ContractWithCustomerLiabilityTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_NatureOfOperationsAndBasisOfPresentationPolicyPolicyTextBlock" name="NatureOfOperationsAndBasisOfPresentationPolicyPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_OtherFinancialDataDisclosureTextBlock" name="OtherFinancialDataDisclosureTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_RestrictedStockAndCashAwardsTextBlock" name="RestrictedStockAndCashAwardsTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_ScheduleOfBusinessAcquisitionAcquisitionOfAssetsTableTextBlock" name="ScheduleOfBusinessAcquisitionAcquisitionOfAssetsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_ScheduleOfBusinessAcquisitionProFormaTableTextBlock" name="ScheduleOfBusinessAcquisitionProFormaTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_ScheduleOfOffBalanceSheetCommitmentsTableTextBlock" name="ScheduleOfOffBalanceSheetCommitmentsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_ScheduleOfRevenueByProductTypeTableTextBlock" name="ScheduleOfRevenueByProductTypeTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_StockOptionPlansTextBlock" name="StockOptionPlansTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="ajg_SummaryOfNotionalAndFairValuesOfDerivativeInstrumentsTableTextBlock" name="SummaryOfNotionalAndFairValuesOfDerivativeInstrumentsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
</xsd:schema>
