<SEC-DOCUMENT>0001179110-16-028246.txt : 20160803
<SEC-HEADER>0001179110-16-028246.hdr.sgml : 20160803
<ACCEPTANCE-DATETIME>20160803194306
ACCESSION NUMBER:		0001179110-16-028246
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20160801
FILED AS OF DATE:		20160803
DATE AS OF CHANGE:		20160803

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			OSI SYSTEMS INC
		CENTRAL INDEX KEY:			0001039065
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				330238801
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		12525 CHADRON AVE
		CITY:			HAWTHORNE
		STATE:			CA
		ZIP:			90250
		BUSINESS PHONE:		3109780516

	MAIL ADDRESS:	
		STREET 1:		12525 CHADRON AVENUE
		CITY:			HAWTHORNE
		STATE:			CA
		ZIP:			90250

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Chin Pak Khong
		CENTRAL INDEX KEY:			0001642600

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23125
		FILM NUMBER:		161805309

	MAIL ADDRESS:	
		STREET 1:		12525 CHADRON AVE
		CITY:			HAWTHORNE
		STATE:			CA
		ZIP:			90250
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-08-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001039065</issuerCik>
        <issuerName>OSI SYSTEMS INC</issuerName>
        <issuerTradingSymbol>OSIS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001642600</rptOwnerCik>
            <rptOwnerName>Chin Pak Khong</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>12525 CHADRON AVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HAWTHORNE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90250</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Pres., Rapiscan Systems</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Copmmon Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2016-08-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3334</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10334</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Shares are restricted stock units issued to the Reporting Person pursuant to the OSI Systems, Inc. 2012 Incentive Award Plan. Vesting and amount of shares is subject to achievement of performance targets.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Pak Khong Chin</signatureName>
        <signatureDate>2016-08-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
