content: <?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:com="http://www.sec.gov/edgar/common">
    <headerData>
      <submissionType>144</submissionType>
      <filerInfo>
        <filer>
          <filerCredentials>
            <cik>0001777322</cik>
            <ccc>XXXXXXXX</ccc>
          </filerCredentials>
        </filer>
        <liveTestFlag>LIVE</liveTestFlag>
  
  
  
      </filerInfo>
    </headerData>
    <formData>
      <issuerInfo>
        <issuerCik>0000029989</issuerCik>
        <issuerName>OMNICOM GROUP INC.</issuerName>
        <secFileNumber>001-10551</secFileNumber>
        <issuerAddress>
          <com:street1>280 PARK AVENUE</com:street1>
          <com:city>NEW YORK</com:city>
          <com:stateOrCountry>NY</com:stateOrCountry>
          <com:zipCode>10017</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>2124153600</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Tarlowe Rochelle M.</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Officer</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>Fidelity Brokerage Services LLC</name>
          <address>
            <com:street1>900 Salem Street</com:street1>
            <com:city>Smithfield</com:city>
            <com:stateOrCountry>RI</com:stateOrCountry>
            <com:zipCode>02917</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>3000</noOfUnitsSold>
        <aggregateMarketValue>297510.00</aggregateMarketValue>
        <noOfUnitsOutstanding>195648843</noOfUnitsOutstanding>
        <approxSaleDate>08/26/2024</approxSaleDate>
        <securitiesExchangeName>NYSE</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/15/2023</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>7</amountOfSecuritiesAcquired>
        <paymentDate>08/15/2023</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>05/15/2024</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>1327</amountOfSecuritiesAcquired>
        <paymentDate>05/15/2024</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/15/2024</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>1666</amountOfSecuritiesAcquired>
        <paymentDate>08/15/2024</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <noticeSignature>
        <noticeDate>08/26/2024</noticeDate>
        <signature>/s/Wade Moss, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Rochelle Tarlowe</signature>
      </noticeSignature>
    </formData>
  </edgarSubmission>
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text: 144
  0001777322
  XXXXXXXX
  LIVE
  0000029989
  OMNICOM GROUP INC.
  001-10551
  280 PARK AVENUE
  NEW YORK
  NY
  10017
  2124153600
  Tarlowe Rochelle M.
  Officer
  Common
  Fidelity Brokerage Services LLC
  900 Salem Street
  Smithfield
  RI
  02917
  3000
  297510.00
  195648843
  08/26/2024
  NYSE
  Common
  08/15/2023
  Restricted Stock Vesting
  Issuer
  N
  7
  08/15/2023
  Compensation
  Common
  05/15/2024
  Restricted Stock Vesting
  Issuer
  N
  1327
  05/15/2024
  Compensation
  Common
  08/15/2024
  Restricted Stock Vesting
  Issuer
  N
  1666
  08/15/2024
  Compensation
  Y
  08/26/2024
  /s/Wade Moss, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Rochelle Tarlowe