<?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:ns2="http://www.sec.gov/edgar/common">
    <headerData>
        <submissionType>144</submissionType>
        <filerInfo>
            <filer>
                <filerCredentials>
                    <cik>0001792618</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>
                <ns2:street1>16 Jonspin Road</ns2:street1>
                <ns2:city>Wilmington</ns2:city>
                <ns2:stateOrCountry>MA</ns2:stateOrCountry>
                <ns2:zipCode>01887</ns2:zipCode>
            </issuerAddress>
            <issuerContactPhone>(978) 253-6200</issuerContactPhone>
            <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>ROBERT FIORDALICE</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
            <relationshipsToIssuer>
                <relationshipToIssuer>Officer</relationshipToIssuer>
            </relationshipsToIssuer>
        </issuerInfo>
        <securitiesInformation>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <brokerOrMarketmakerDetails>
                <name>Morgan Stanley Smith Barney LLC</name>
                <address>
                    <ns2:street1>1 New York Plaza</ns2:street1>
                    <ns2:street2>38th Floor</ns2:street2>
                    <ns2:city>New York</ns2:city>
                    <ns2:stateOrCountry>NY</ns2:stateOrCountry>
                    <ns2:zipCode>10004</ns2:zipCode>
                </address>
            </brokerOrMarketmakerDetails>
            <noOfUnitsSold>780</noOfUnitsSold>
            <aggregateMarketValue>78975.00</aggregateMarketValue>
            <noOfUnitsOutstanding>48945470</noOfUnitsOutstanding>
            <approxSaleDate>05/18/2023</approxSaleDate>
            <securitiesExchangeName>NYSE</securitiesExchangeName>
        </securitiesInformation>
        <securitiesToBeSold>
            <securitiesClassTitle>COMMON</securitiesClassTitle>
            <acquiredDate>06/01/2020</acquiredDate>
            <natureOfAcquisitionTransaction>Restricted Stock</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>ISSUER</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>780</amountOfSecuritiesAcquired>
            <paymentDate>06/01/2020</paymentDate>
            <natureOfPayment>Not Applicable</natureOfPayment>
        </securitiesToBeSold>
        <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>ROBERT FIORDALICE</name>
                <address>
                    <ns2:street1>16 Jonspin Road</ns2:street1>
                    <ns2:city>Wilmington</ns2:city>
                    <ns2:stateOrCountry>MA</ns2:stateOrCountry>
                    <ns2:zipCode>01887</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>05/17/2023</saleDate>
            <amountOfSecuritiesSold>768</amountOfSecuritiesSold>
            <grossProceeds>74649.60</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>ROBERT FIORDALICE</name>
                <address>
                    <ns2:street1>16 Jonspin Road</ns2:street1>
                    <ns2:city>Wilmington</ns2:city>
                    <ns2:stateOrCountry>MA</ns2:stateOrCountry>
                    <ns2:zipCode>01887</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>05/15/2023</saleDate>
            <amountOfSecuritiesSold>669</amountOfSecuritiesSold>
            <grossProceeds>62317.35</grossProceeds>
        </securitiesSoldInPast3Months>
        <noticeSignature>
            <noticeDate>05/18/2023</noticeDate>
            <planAdoptionDates>
                <planAdoptionDate>06/10/2022</planAdoptionDate>
            </planAdoptionDates>
            <signature>/s/ Robert William Fiordalice</signature>
        </noticeSignature>
    </formData>
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144
0001792618
XXXXXXXX
LIVE
0000704532
ONTO INNOVATION INC
001-39110
16 Jonspin Road
Wilmington
MA
01887
(978) 253-6200
ROBERT FIORDALICE
Officer
Common
Morgan Stanley Smith Barney LLC
1 New York Plaza
38th Floor
New York
NY
10004
780
78975.00
48945470
05/18/2023
NYSE
COMMON
06/01/2020
Restricted Stock
ISSUER
N
780
06/01/2020
Not Applicable
N
ROBERT FIORDALICE
16 Jonspin Road
Wilmington
MA
01887
Common
05/17/2023
768
74649.60
ROBERT FIORDALICE
16 Jonspin Road
Wilmington
MA
01887
Common
05/15/2023
669
62317.35
05/18/2023
06/10/2022
/s/ Robert William Fiordalice