<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-08-24</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000723888</issuerCik>
        <issuerName>JUNO LIGHTING INC</issuerName>
        <issuerTradingSymbol>JUNO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001225295</rptOwnerCik>
            <rptOwnerName>LEBLANC EDWARD A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1394 S THIRD ST</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MEANE</rptOwnerCity>
            <rptOwnerState>NC</rptOwnerState>
            <rptOwnerZipCode>27302</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>20.2517</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-08-24</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>14100</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2008-06-24</value>
            </exerciseDate>
            <expirationDate>
                <value>2013-06-24</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>14100</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>20.2517</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-08-24</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>750</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2009-09-10</value>
            </exerciseDate>
            <expirationDate>
                <value>2014-09-10</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>750</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Pursuant to an Agreement and Plan of Merger, dated as of June 29, 2005 (the &quot;Merger Agreement&quot;), by and among Juno Lighting, Inc. (&quot;Company&quot;), Square D Company (&quot;Square D&quot;), and Hera Acquisition Corp. (&quot;Hera&quot;), on August 24, 2005, the Company was merged with and into Hera (the &quot;Merger&quot;). As a result all of the Reporting Person's option was canceled in the Merger in exchange for a cash payment representing the difference between the exercise price of the option and the purchase price of $44 per underlying share of common stock.</footnote>
        <footnote id="F2">This option was canceled in the Merger in exchange for a cash payment representing the difference between the exercise price of the option and the purchase price of $44 per underlying share of common stock.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Edward A. LeBlanc</signatureName>
        <signatureDate>2005-09-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0202
4
2005-08-24
0
0000723888
JUNO LIGHTING INC
JUNO
0001225295
LEBLANC EDWARD A
1394 S THIRD ST
MEANE
NC
27302
1
0
0
0
Stock Option (right to buy)
20.2517
2005-08-24
4
J
0
14100
D
2008-06-24
2013-06-24
Common Stock
14100
0
D
Stock Option (right to buy)
20.2517
2005-08-24
4
J
0
750
D
2009-09-10
2014-09-10
Common Stock
750
0
D
Pursuant to an Agreement and Plan of Merger, dated as of June 29, 2005 (the "Merger Agreement"), by and among Juno Lighting, Inc. ("Company"), Square D Company ("Square D"), and Hera Acquisition Corp. ("Hera"), on August 24, 2005, the Company was merged with and into Hera (the "Merger"). As a result all of the Reporting Person's option was canceled in the Merger in exchange for a cash payment representing the difference between the exercise price of the option and the purchase price of $44 per underlying share of common stock.
This option was canceled in the Merger in exchange for a cash payment representing the difference between the exercise price of the option and the purchase price of $44 per underlying share of common stock.
Edward A. LeBlanc
2005-09-01