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>0001325550</cik>
            <ccc>XXXXXXXX</ccc>
          </filerCredentials>
        </filer>
        <liveTestFlag>LIVE</liveTestFlag>
  
  
      </filerInfo>
    </headerData>
    <formData>
      <issuerInfo>
        <issuerCik>0000704532</issuerCik>
        <issuerName>ONTO INNOVATION INC.</issuerName>
        <secFileNumber>001-39110</secFileNumber>
        <issuerAddress>
          <com:street1>16 JONSPIN ROAD</com:street1>
          <com:city>WILMINGTON</com:city>
          <com:stateOrCountry>MA</com:stateOrCountry>
          <com:zipCode>01887</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>9782536200</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Plisinski Michael P</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Officer</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>common</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>Fidelity Brokerage Services LLC</name>
          <address>
            <com:street1>245 Summer Street</com:street1>
            <com:city>Boston</com:city>
            <com:stateOrCountry>MA</com:stateOrCountry>
            <com:zipCode>02110</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>35000</noOfUnitsSold>
        <aggregateMarketValue>7671808.07</aggregateMarketValue>
        <noOfUnitsOutstanding>49391299</noOfUnitsOutstanding>
        <approxSaleDate>01/21/2025</approxSaleDate>
        <securitiesExchangeName>NYSE</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>11/09/2018</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>11954</amountOfSecuritiesAcquired>
        <paymentDate>11/09/2018</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>10/01/2016</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>773</amountOfSecuritiesAcquired>
        <paymentDate>10/01/2016</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/22/2016</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>1220</amountOfSecuritiesAcquired>
        <paymentDate>02/22/2016</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/19/2016</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>2640</amountOfSecuritiesAcquired>
        <paymentDate>02/19/2016</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>01/31/2016</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>1547</amountOfSecuritiesAcquired>
        <paymentDate>01/31/2016</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>01/28/2016</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>2168</amountOfSecuritiesAcquired>
        <paymentDate>01/28/2016</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>01/26/2016</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>1394</amountOfSecuritiesAcquired>
        <paymentDate>01/26/2016</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>01/25/2016</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>1650</amountOfSecuritiesAcquired>
        <paymentDate>01/25/2016</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>10/01/2015</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>773</amountOfSecuritiesAcquired>
        <paymentDate>10/01/2015</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/22/2015</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>1205</amountOfSecuritiesAcquired>
        <paymentDate>02/22/2015</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/20/2015</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>722</amountOfSecuritiesAcquired>
        <paymentDate>02/20/2015</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>01/31/2015</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>750</amountOfSecuritiesAcquired>
        <paymentDate>01/31/2015</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>01/26/2015</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>1393</amountOfSecuritiesAcquired>
        <paymentDate>01/26/2015</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>01/25/2015</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>1648</amountOfSecuritiesAcquired>
        <paymentDate>01/25/2015</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/22/2014</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>1005</amountOfSecuritiesAcquired>
        <paymentDate>02/22/2014</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/10/2014</acquiredDate>
        <natureOfAcquisitionTransaction>Compensation</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>4158</amountOfSecuritiesAcquired>
        <paymentDate>02/10/2014</paymentDate>
        <natureOfPayment>N/A</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>Michael Plisinski c/o ONTO INNOVATION INC.</name>
          <address>
            <com:street1>16 JONSPIN ROAD</com:street1>
            <com:city>WILMINGTON</com:city>
            <com:stateOrCountry>MA</com:stateOrCountry>
            <com:zipCode>01887</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <saleDate>01/14/2025</saleDate>
        <amountOfSecuritiesSold>20000</amountOfSecuritiesSold>
        <grossProceeds>4003917.08</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>Michael Plisinski c/o ONTO INNOVATION INC.</name>
          <address>
            <com:street1>16 JONSPIN ROAD,</com:street1>
            <com:city>WILMINGTON</com:city>
            <com:stateOrCountry>MA</com:stateOrCountry>
            <com:zipCode>01887</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <saleDate>01/16/2025</saleDate>
        <amountOfSecuritiesSold>30000</amountOfSecuritiesSold>
        <grossProceeds>6337183.73</grossProceeds>
      </securitiesSoldInPast3Months>
      <noticeSignature>
        <noticeDate>01/21/2025</noticeDate>
        <planAdoptionDates>
          <planAdoptionDate>08/26/2024</planAdoptionDate>
        </planAdoptionDates>
        <signature>/s/ Audrey Skillern as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Michael Plisinski</signature>
      </noticeSignature>
    </formData>
  </edgarSubmission>
metadata_documents: [{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 11910}]
text: 144
  0001325550
  XXXXXXXX
  LIVE
  0000704532
  ONTO INNOVATION INC.
  001-39110
  16 JONSPIN ROAD
  WILMINGTON
  MA
  01887
  9782536200
  Plisinski Michael P
  Officer
  common
  Fidelity Brokerage Services LLC
  245 Summer Street
  Boston
  MA
  02110
  35000
  7671808.07
  49391299
  01/21/2025
  NYSE
  Common
  11/09/2018
  Compensation
  Issuer
  N
  11954
  11/09/2018
  N/A
  Common
  10/01/2016
  Compensation
  Issuer
  N
  773
  10/01/2016
  N/A
  Common
  02/22/2016
  Compensation
  Issuer
  N
  1220
  02/22/2016
  N/A
  Common
  02/19/2016
  Compensation
  Issuer
  N
  2640
  02/19/2016
  N/A
  Common
  01/31/2016
  Compensation
  Issuer
  N
  1547
  01/31/2016
  N/A
  Common
  01/28/2016
  Compensation
  Issuer
  N
  2168
  01/28/2016
  N/A
  Common
  01/26/2016
  Compensation
  Issuer
  N
  1394
  01/26/2016
  N/A
  Common
  01/25/2016
  Compensation
  Issuer
  N
  1650
  01/25/2016
  N/A
  Common
  10/01/2015
  Compensation
  Issuer
  N
  773
  10/01/2015
  N/A
  Common
  02/22/2015
  Compensation
  Issuer
  N
  1205
  02/22/2015
  N/A
  Common
  02/20/2015
  Compensation
  Issuer
  N
  722
  02/20/2015
  N/A
  Common
  01/31/2015
  Compensation
  Issuer
  N
  750
  01/31/2015
  N/A
  Common
  01/26/2015
  Compensation
  Issuer
  N
  1393
  01/26/2015
  N/A
  Common
  01/25/2015
  Compensation
  Issuer
  N
  1648
  01/25/2015
  N/A
  Common
  02/22/2014
  Compensation
  Issuer
  N
  1005
  02/22/2014
  N/A
  Common
  02/10/2014
  Compensation
  Issuer
  N
  4158
  02/10/2014
  N/A
  N
  Michael Plisinski c/o ONTO INNOVATION INC.
  16 JONSPIN ROAD
  WILMINGTON
  MA
  01887
  Common Stock
  01/14/2025
  20000
  4003917.08
  Michael Plisinski c/o ONTO INNOVATION INC.
  16 JONSPIN ROAD,
  WILMINGTON
  MA
  01887
  Common Stock
  01/16/2025
  30000
  6337183.73
  01/21/2025
  08/26/2024
  /s/ Audrey Skillern as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Michael Plisinski