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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-11-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000827809</issuerCik>
        <issuerName>QLT INC/BC</issuerName>
        <issuerTradingSymbol>NVLN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001243004</rptOwnerCik>
            <rptOwnerName>SMITH SANDFORD D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O NOVELION THERAPEUTICS INC.</rptOwnerStreet1>
            <rptOwnerStreet2>997 GREAT NORTHERN WAY, SUITE 250</rptOwnerStreet2>
            <rptOwnerCity>VANCOUVER</rptOwnerCity>
            <rptOwnerState>A1</rptOwnerState>
            <rptOwnerZipCode>V5T 4T5</rptOwnerZipCode>
            <rptOwnerStateDescription>BRITISH COLUMBIA, CANADA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Shares, without par value</value>
            </securityTitle>
            <transactionDate>
                <value>2016-11-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2963</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2963</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2016-11-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>9115</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Shares</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>9115</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9115</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Received in exchange for 2,890 shares of Aegerion Pharmaceuticals, Inc. (&quot;Aegerion&quot;) common stock pursuant to the Agreement and Plan of Merger (the &quot;Merger Agreement&quot;), dated as of June 14, 2016, by and among the Issuer, Aegerion and Isotope Acquisition Corp. (&quot;Isotope&quot;), pursuant to which Isotope was merged with and into Aegerion, effective November 29, 2016.  On the date prior to the effective time of the merger, the closing price of Aegerion's common stock was $1.87 per share and the closing price of the Issuer's common shares was $1.83 per share.</footnote>
        <footnote id="F2">Each restricted stock unit represents a contingent right to receive one common share of the Issuer.</footnote>
        <footnote id="F3">16.67% of the grant vested on January 27, 2016 and an additional 16.67% vested on July 27, 2016. Subject to the Reporting Person continuing to serve as a member of the board of the Issuer, an additional 16.67% of the grant will vest on each of January 27, 2017, July 27, 2017, January 27, 2018 and August 21, 2018.</footnote>
        <footnote id="F4">Pursuant to the Merger Agreement, each restricted stock unit with respect to common stock of Aegerion (&quot;Aegerion RSU&quot;) that was outstanding as of immediately prior to the effective time of the merger was exchanged for a restricted stock unit with respect to a number of common shares of the Issuer (&quot;Issuer RSU&quot;) equal to the product obtained by multiplying (i) the total number of shares of common stock of Aegerion subject to the Aegerion RSU immediately prior to the effective time of the merger by (ii) the exchange ratio of 1.0256. Each Issuer RSU is subject to the same terms and conditions applicable to the corresponding Aegerion RSU and the agreements evidencing grant of the Aegerion RSUs thereunder, including vesting terms, but excluding any terms that are rendered inoperative solely by reason of the merger.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Jennifer Fitzpatrick, Attorney-in-fact</signatureName>
        <signatureDate>2016-12-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
