<SEC-DOCUMENT>0002022859-25-000058.txt : 20250523
<SEC-HEADER>0002022859-25-000058.hdr.sgml : 20250523
<ACCEPTANCE-DATETIME>20250523160904
ACCESSION NUMBER:		0002022859-25-000058
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250521
FILED AS OF DATE:		20250523
DATE AS OF CHANGE:		20250523

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Kelley Stephen Douglas
		CENTRAL INDEX KEY:			0001443674
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39110
		FILM NUMBER:		25982255

	MAIL ADDRESS:	
		STREET 1:		1900 S. PRICE ROAD
		CITY:			CHANDLER
		STATE:			AZ
		ZIP:			85286

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ONTO INNOVATION INC.
		CENTRAL INDEX KEY:			0000704532
		STANDARD INDUSTRIAL CLASSIFICATION:	MEASURING & CONTROLLING DEVICES, NEC [3829]
		ORGANIZATION NAME:           	08 Industrial Applications and Services
		EIN:				942276314
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1226

	BUSINESS ADDRESS:	
		STREET 1:		16 JONSPIN ROAD
		CITY:			WILMINGTON
		STATE:			MA
		ZIP:			01887
		BUSINESS PHONE:		9782536200

	MAIL ADDRESS:	
		STREET 1:		16 JONSPIN ROAD
		CITY:			WILMINGTON
		STATE:			MA
		ZIP:			01887

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Onto Innovation Inc.
		DATE OF NAME CHANGE:	20191025

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	NANOMETRICS INC
		DATE OF NAME CHANGE:	19920703
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgardoc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-05-21</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000704532</issuerCik>
        <issuerName>ONTO INNOVATION INC.</issuerName>
        <issuerTradingSymbol>ONTO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001443674</rptOwnerCik>
            <rptOwnerName>Kelley Stephen Douglas</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ONTO INNOVATION INC.</rptOwnerStreet1>
            <rptOwnerStreet2>16 JONSPIN ROAD</rptOwnerStreet2>
            <rptOwnerCity>WILMINGTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>01887</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-05-21</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2114</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5623</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The Reporting Person was granted restricted stock units (&quot;RSUs&quot;), each of which represents a contingent right to receive one (1) share of ONTO Common Stock. 100% of the shares of Common Stock subject to the RSU vest one (1) year from the grant date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By: Mark R. Slicer For: Stephen D. Kelley</signatureName>
        <signatureDate>2025-05-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
