content: <?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:com="http://www.sec.gov/edgar/common">
    <!-- Generated by Workiva -->
    <headerData>
      <submissionType>144</submissionType>
      <filerInfo>
        <filer>
          <filerCredentials>
            <cik>0001227348</cik>
            <ccc>XXXXXXXX</ccc>
          </filerCredentials>
        </filer>
        <liveTestFlag>LIVE</liveTestFlag>
  
  
  
      </filerInfo>
    </headerData>
    <formData>
      <issuerInfo>
        <issuerCik>0001288847</issuerCik>
        <issuerName>Five9, Inc.</issuerName>
        <secFileNumber>001-36383</secFileNumber>
        <issuerAddress>
          <com:street1>3001 Bishop Drive, Suite 350</com:street1>
          <com:city>San Ramon</com:city>
          <com:stateOrCountry>CA</com:stateOrCountry>
          <com:zipCode>94583</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>925-201-2000</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Barry Zwarenstein</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Officer</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>J.P. Morgan Securities LLC</name>
          <address>
            <com:street1>390 Madison Avenue</com:street1>
            <com:street2>6th Floor</com:street2>
            <com:city>New York</com:city>
            <com:stateOrCountry>NY</com:stateOrCountry>
            <com:zipCode>10017</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>46273</noOfUnitsSold>
        <aggregateMarketValue>1970767</aggregateMarketValue>
        <noOfUnitsOutstanding>73867985</noOfUnitsOutstanding>
        <approxSaleDate>06/10/2024</approxSaleDate>
        <securitiesExchangeName>NASDAQ</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <acquiredDate>06/03/2024</acquiredDate>
        <natureOfAcquisitionTransaction>RSU Vesting received by Barry Zwarenstein</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>12521</amountOfSecuritiesAcquired>
        <paymentDate>06/03/2024</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <acquiredDate>09/03/2015</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation received by the Barry Zwarenstein and Mahbobeh Hirmand Trust between 09/03/15 and 06/03/23</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>33752</amountOfSecuritiesAcquired>
        <paymentDate>06/03/2023</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <remarks>Of the shares filed today,  12,521 shares were filed for Barry Zwarenstein and 33,752 shares were filed for the Barry Zwarenstein and Mahbobeh Hirmand Trust,  Barry Zwarenstein  as Trustee.</remarks>
      <noticeSignature>
        <noticeDate>06/10/2024</noticeDate>
        <planAdoptionDates>
          <planAdoptionDate>03/04/2024</planAdoptionDate>
        </planAdoptionDates>
        <signature>/s/ J.P. Morgan Securities LLC as agent and attorney-in-fact for Barry Zwarenstein</signature>
      </noticeSignature>
    </formData>
  </edgarSubmission>
metadata_documents: [{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 3838}]
text: 144
  0001227348
  XXXXXXXX
  LIVE
  0001288847
  Five9, Inc.
  001-36383
  3001 Bishop Drive, Suite 350
  San Ramon
  CA
  94583
  925-201-2000
  Barry Zwarenstein
  Officer
  Common Stock
  J.P. Morgan Securities LLC
  390 Madison Avenue
  6th Floor
  New York
  NY
  10017
  46273
  1970767
  73867985
  06/10/2024
  NASDAQ
  Common Stock
  06/03/2024
  RSU Vesting received by Barry Zwarenstein
  Issuer
  N
  12521
  06/03/2024
  Compensation
  Common Stock
  09/03/2015
  Compensation received by the Barry Zwarenstein and Mahbobeh Hirmand Trust between 09/03/15 and 06/03/23
  Issuer
  N
  33752
  06/03/2023
  Compensation
  Y
  Of the shares filed today,  12,521 shares were filed for Barry Zwarenstein and 33,752 shares were filed for the Barry Zwarenstein and Mahbobeh Hirmand Trust,  Barry Zwarenstein  as Trustee.
  06/10/2024
  03/04/2024
  /s/ J.P. Morgan Securities LLC as agent and attorney-in-fact for Barry Zwarenstein