-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Kj5mAVsS8ddlcQ3N2EeaRv3B55efunBAA+frxQRbuk1apyozOysFAEvRH3zMC8jC
 gJrTg8nuleQmNxzWd/ebaA==

<SEC-DOCUMENT>0001104659-03-015746.txt : 20030728
<SEC-HEADER>0001104659-03-015746.hdr.sgml : 20030728
<ACCEPTANCE-DATETIME>20030725193208
ACCESSION NUMBER:		0001104659-03-015746
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030723
FILED AS OF DATE:		20030728

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MCNEALY SCOTT G
		CENTRAL INDEX KEY:			0001220062

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-15086
		FILM NUMBER:		03804465

	BUSINESS ADDRESS:	
		STREET 1:		C/O SUN MICROSYSTEMS INC
		STREET 2:		4120 NETWORK CIRCLE M/S SCA12-202
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95054
		BUSINESS PHONE:		6509601300

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SUN MICROSYSTEMS INC
		CENTRAL INDEX KEY:			0000709519
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRONIC COMPUTERS [3571]
		IRS NUMBER:				942805249
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		4150 NETWORK CIRCLE
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95054
		BUSINESS PHONE:		6509601300

	MAIL ADDRESS:	
		STREET 1:		4150 NETWORK CIRCLE
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95054
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>a4.xml
<DESCRIPTION>4
<TEXT>
<XML>
<?xml version="1.0" encoding="utf-8"?>
<ownershipDocument>
    <schemaVersion>X0101</schemaVersion>

    <documentType>4</documentType>
  <periodOfReport>2003-07-23</periodOfReport>
  <notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000709519</issuerCik>
        <issuerName>SUN MICROSYSTEMS INC</issuerName>
        <issuerTradingSymbol>SUNW</issuerTradingSymbol>
  </issuer>
  <reportingOwner>
    <reportingOwnerId>
            <rptOwnerCik>0001220062</rptOwnerCik>
            <rptOwnerName>MCNEALY SCOTT G</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
      <isDirector>1</isDirector>
      <isOfficer>1</isOfficer>
      <isTenPercentOwner>0</isTenPercentOwner>
      <isOther>0</isOther>
      <officerTitle>Chairman, President and CEO</officerTitle>
    </reportingOwnerRelationship>
  </reportingOwner>
  <nonDerivativeSecurity>
    <securityTitle>
      <value>Common Stock</value>
    </securityTitle>
    <transactionDate>
      <value>1988-08-08</value>
      <footnoteId id="F1"/>
    </transactionDate>
    <transactionCoding>
      <transactionFormType>4</transactionFormType>
      <transactionCode>J</transactionCode>
      <equitySwapInvolved>0</equitySwapInvolved>
      <footnoteId id="F2"/>
    </transactionCoding>
    <transactionTimeliness>
      <value/>
    </transactionTimeliness>
    <transactionAmounts>
      <transactionShares>
        <value>0</value>
      </transactionShares>
      <transactionValue>
        <value>0</value>
      </transactionValue>
      <transactionAcquiredDisposedCode>
        <value>A</value>
      </transactionAcquiredDisposedCode>
    </transactionAmounts>
    <postTransactionAmounts>
      <sharesOwnedFollowingTransaction>
        <value>56081290</value>
        <footnoteId id="F3"/>
      </sharesOwnedFollowingTransaction>
    </postTransactionAmounts>
    <ownershipNature>
      <directOrIndirectOwnership>
        <value>D</value>
      </directOrIndirectOwnership>
    </ownershipNature>
  </nonDerivativeSecurity>
  <nonDerivativeSecurity>
    <securityTitle>
      <value>Common Stock</value>
    </securityTitle>
    <transactionDate>
      <value>1988-08-08</value>
      <footnoteId id="F4"/>
    </transactionDate>
    <transactionCoding>
      <transactionFormType>4</transactionFormType>
      <transactionCode>J</transactionCode>
      <equitySwapInvolved>0</equitySwapInvolved>
      <footnoteId id="F5"/>
    </transactionCoding>
    <transactionTimeliness>
      <value/>
    </transactionTimeliness>
    <transactionAmounts>
      <transactionShares>
        <value>0</value>
      </transactionShares>
      <transactionValue>
        <value>0</value>
      </transactionValue>
      <transactionAcquiredDisposedCode>
        <value>A</value>
      </transactionAcquiredDisposedCode>
    </transactionAmounts>
    <postTransactionAmounts>
      <sharesOwnedFollowingTransaction>
        <value>1451</value>
      </sharesOwnedFollowingTransaction>
    </postTransactionAmounts>
    <ownershipNature>
      <directOrIndirectOwnership>
        <value>I</value>
      </directOrIndirectOwnership>
      <natureOfOwnership>
        <value>By wife for son Dakota</value>
      </natureOfOwnership>
    </ownershipNature>
  </nonDerivativeSecurity>
  <nonDerivativeSecurity>
    <securityTitle>
      <value>Common Stock</value>
    </securityTitle>
    <transactionDate>
      <value>1988-08-08</value>
      <footnoteId id="F4"/>
    </transactionDate>
    <transactionCoding>
      <transactionFormType>4</transactionFormType>
      <transactionCode>J</transactionCode>
      <equitySwapInvolved>0</equitySwapInvolved>
      <footnoteId id="F5"/>
    </transactionCoding>
    <transactionTimeliness>
      <value/>
    </transactionTimeliness>
    <transactionAmounts>
      <transactionShares>
        <value>0</value>
      </transactionShares>
      <transactionValue>
        <value>0</value>
      </transactionValue>
      <transactionAcquiredDisposedCode>
        <value>A</value>
      </transactionAcquiredDisposedCode>
    </transactionAmounts>
    <postTransactionAmounts>
      <sharesOwnedFollowingTransaction>
        <value>1451</value>
      </sharesOwnedFollowingTransaction>
    </postTransactionAmounts>
    <ownershipNature>
      <directOrIndirectOwnership>
        <value>I</value>
      </directOrIndirectOwnership>
      <natureOfOwnership>
        <value>By wife for son Maverick</value>
      </natureOfOwnership>
    </ownershipNature>
  </nonDerivativeSecurity>
  <nonDerivativeSecurity>
    <securityTitle>
      <value>Common Stock</value>
    </securityTitle>
    <transactionDate>
      <value>1988-08-08</value>
      <footnoteId id="F4"/>
    </transactionDate>
    <transactionCoding>
      <transactionFormType>4</transactionFormType>
      <transactionCode>J</transactionCode>
      <equitySwapInvolved>0</equitySwapInvolved>
      <footnoteId id="F5"/>
    </transactionCoding>
    <transactionTimeliness>
      <value/>
    </transactionTimeliness>
    <transactionAmounts>
      <transactionShares>
        <value>0</value>
      </transactionShares>
      <transactionValue>
        <value>0</value>
      </transactionValue>
      <transactionAcquiredDisposedCode>
        <value>A</value>
      </transactionAcquiredDisposedCode>
    </transactionAmounts>
    <postTransactionAmounts>
      <sharesOwnedFollowingTransaction>
        <value>1451</value>
      </sharesOwnedFollowingTransaction>
    </postTransactionAmounts>
    <ownershipNature>
      <directOrIndirectOwnership>
        <value>I</value>
      </directOrIndirectOwnership>
      <natureOfOwnership>
        <value>By wife for son Scout</value>
      </natureOfOwnership>
    </ownershipNature>
  </nonDerivativeSecurity>
  <nonDerivativeSecurity>
    <securityTitle>
      <value>Common Stock</value>
    </securityTitle>
    <transactionDate>
      <value>1988-08-08</value>
      <footnoteId id="F4"/>
    </transactionDate>
    <transactionCoding>
      <transactionFormType>4</transactionFormType>
      <transactionCode>J</transactionCode>
      <equitySwapInvolved>0</equitySwapInvolved>
      <footnoteId id="F5"/>
    </transactionCoding>
    <transactionTimeliness>
      <value/>
    </transactionTimeliness>
    <transactionAmounts>
      <transactionShares>
        <value>0</value>
      </transactionShares>
      <transactionValue>
        <value>0</value>
      </transactionValue>
      <transactionAcquiredDisposedCode>
        <value>A</value>
      </transactionAcquiredDisposedCode>
    </transactionAmounts>
    <postTransactionAmounts>
      <sharesOwnedFollowingTransaction>
        <value>1451</value>
      </sharesOwnedFollowingTransaction>
    </postTransactionAmounts>
    <ownershipNature>
      <directOrIndirectOwnership>
        <value>I</value>
      </directOrIndirectOwnership>
      <natureOfOwnership>
        <value>By wife for son Colt</value>
      </natureOfOwnership>
    </ownershipNature>
  </nonDerivativeSecurity>
  <derivativeSecurity>
    <securityTitle>
      <value>Option (right to buy)</value>
    </securityTitle>
    <conversionOrExercisePrice>
      <value>3.85</value>
    </conversionOrExercisePrice>
    <transactionDate>
      <value>2003-07-23</value>
    </transactionDate>
    <transactionCoding>
      <transactionFormType>4</transactionFormType>
      <transactionCode>A</transactionCode>
      <equitySwapInvolved>0</equitySwapInvolved>
    </transactionCoding>
    <transactionTimeliness>
      <value/>
    </transactionTimeliness>
    <transactionAmounts>
      <transactionShares>
        <value>1500000</value>
      </transactionShares>
      <transactionValue>
        <value>0</value>
        <footnoteId id="F7"/>
      </transactionValue>
      <transactionAcquiredDisposedCode>
        <value>A</value>
      </transactionAcquiredDisposedCode>
    </transactionAmounts>
    <exerciseDate>
      <value>2004-07-23</value>
      <footnoteId id="F6"/>
    </exerciseDate>
    <expirationDate>
      <value>2013-07-23</value>
    </expirationDate>
    <underlyingSecurity>
      <underlyingSecurityTitle>
        <value>Common Stock</value>
      </underlyingSecurityTitle>
      <underlyingSecurityShares>
        <value>1500000</value>
      </underlyingSecurityShares>
    </underlyingSecurity>
    <postTransactionAmounts>
      <sharesOwnedFollowingTransaction>
        <value>1500000</value>
      </sharesOwnedFollowingTransaction>
    </postTransactionAmounts>
    <ownershipNature>
      <directOrIndirectOwnership>
        <value>D</value>
      </directOrIndirectOwnership>
    </ownershipNature>
  </derivativeSecurity>
  <footnotes>
    <footnote id="F1">In the Section 16 Electronic Reporting Frequently Asked Questions released by the SEC on May 1, 2003, the SEC has designated "08/08/1988" as a "dummy date" until the electronic system is modified.  This line reports end of period direct holdings for this reporting person, and 08/08/1988 is not a transaction date related to these securities.</footnote>
    <footnote id="F2">There has been no transaction in the direct holdings for this reporting person.</footnote>
    <footnote id="F3">Reflects 1,792 Shares purchased under Sun Microsystems, Inc. 1990 Employee Stock Purchase Plan on April 30, 2003.</footnote>
    <footnote id="F4">In the Section 16 Electronic Reporting Frequently Asked Questions released by the SEC on May 1, 2003, the SEC has designated "08/08/1988" as a "dummy date" until the electronic system is modified.  This line reports end of period indirect holdings for this reporting person, and 08/08/1988 is not a transaction date related to these securities.</footnote>
    <footnote id="F5">There has been no transaction in the indirect holdings for this reporting person.</footnote>
    <footnote id="F6">The option was granted under Sun Microsystems, Inc. 1990 Long Term Equity Incentive Plan.  Shares vest and become exercisable in five equal annual installments of 300,000 shares beginning July 23, 2004.</footnote>
    <footnote id="F7">The price of the derivative security will be determined at a future date.</footnote>
  </footnotes>
  <ownerSignature>
    <signatureName>/s/ Scott G. McNealy</signatureName>
    <signatureDate>2003-07-25</signatureDate>
  </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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