FORM 6-K

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Report of Foreign Private Issuer

Pursuant to Rule 13a-16 or 15d-16

under the Securities Exchange Act of 1934

For the month of November, 2017

001-14832

(Commission File Number)

CELESTICA INC.

(Translation of registrant’s name into English)

844 Don Mills Road

Toronto, Ontario

Canada M3C 1V7

(416) 448-5800

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

Indicate by check mark whether the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): o

Indicate by check mark whether the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): o

Furnished Herewith (and incorporated by reference herein)

The information contained in this Form 6-K is not incorporated by reference into any registration statement (or into any prospectus that forms a part thereof) filed by Celestica Inc. with the Securities and Exchange Commission.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

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EXHIBIT INDEX

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Exhibit 99.1

CELESTICA ANNOUNCES TSX ACCEPTANCE OF PREVIOUSLY ANNOUNCED NORMAL COURSE ISSUER BID

TORONTO, Canada - Celestica Inc. (NYSE, TSX: CLS), a leader in design, manufacturing and supply chain solutions for the world’s most innovative companies, today announced the Toronto Stock Exchange (the TSX) has accepted the Company’s notice to launch its previously announced Normal Course Issuer Bid (the Bid).

Under the Bid, the Company may repurchase on the open market (or as otherwise permitted), at its discretion during the period commencing on November 13, 2017 and ending on the earlier of November 12, 2018 and the completion of purchases under the Bid, up to 10,459,516 subordinate voting shares, representing approximately 8.4% of the Company’s outstanding subordinate voting shares (7.3% of the subordinate voting shares and multiple voting shares) and approximately 10% of the “public float” of the subordinate voting shares (within the meaning of the rules of the TSX), subject to the normal terms and limitations of such bids. Under the TSX rules, the average daily trading volume of the subordinate voting shares on the TSX during the six months ended October 31, 2017 was 235,679 and, accordingly, daily purchases on the TSX pursuant to the Bid will be limited to 58,919 subordinate voting shares, other than purchases made pursuant to the block purchase exception.  The actual number of subordinate voting shares which may be purchased pursuant to the Bid and the timing of any such purchases will be determined by the management of the Company, subject to applicable law and the rules of the TSX.  In accordance with the TSX rules, the maximum number of subordinate voting shares which may be repurchased for cancellation under the Bid will be reduced by the number of subordinate voting shares purchased for delivery pursuant to stock-based compensation plans.

Purchases are expected to be made through the facilities of the New York Stock Exchange and the Toronto Stock Exchange, or such other permitted means (including through alternative trading systems in Canada), at prevailing market prices or as otherwise permitted.  The Bid will be funded using existing cash resources and draws on its credit facility, and any subordinate voting shares repurchased by the Company under the Bid will be cancelled.

As of November 1, 2017, the Company had 125,086,344 issued and outstanding subordinate voting shares and a “public float” (within the meaning of the rules of the TSX) of 104,595,160 subordinate voting shares.

The Company believes that the purchases are in the best interest of the Company and constitute a desirable use of its funds.

The Company previously implemented a normal course issuer bid for its subordinate voting shares which expired on February 23, 2017.  Under its prior bid, the Company was authorized to purchase up to 10,510,680 subordinate voting shares and repurchased and cancelled 3,204,451 subordinate voting shares.  In the past 12 months, the Company repurchased 2,077,000 subordinate voting shares for delivery pursuant to the Company’s stock-based compensation plans.

About Celestica

Celestica enables the world’s best brands. Through our unrivalled customer-centric approach, we partner with leading companies in aerospace and defense, communications, enterprise, healthtech, industrial, semiconductor capital equipment, and smart energy to deliver solutions for their most complex challenges. A leader in design, manufacturing, hardware platform and supply chain

solutions, Celestica brings global expertise and insight at every stage of product development - from the drawing board to full-scale production and after-market services. With talented teams across North America, Europe and Asia, we imagine, develop and deliver a better future with our customers.

For more information, visit http://www.celestica.com.

Our securities filings can also be accessed at www.sedar.com and www.sec.gov.

Cautionary Note Regarding Forward-Looking Statements

This news release contains forward-looking statements, including those related to the Company’s intention to commence the Bid and the timing and quantity of any purchases of subordinate voting shares under the Bid. Such forward-looking statements may, without limitation, be preceded by, followed by, or include words such as “believes”, “expects”, “anticipates”, “estimates”, “intends”, “plans”, “continues”, “project”, “potential”, “possible”, “contemplate”, “seek”, or similar expressions, or may employ such future or conditional verbs as “may”, “might”, “will”, “could”, “should” or “would”, or may otherwise be indicated as forward-looking statements by grammatical construction, phrasing or context.  For those statements, the Company claims the protection of the safe harbor for forward-looking statements contained in the U.S. Private Securities Litigation Reform Act of 1995 and applicable Canadian securities laws. Forward-looking statements are provided for the purpose of assisting readers in understanding management’s current expectations and plans relating to the future. Readers are cautioned that such information may not be appropriate for other purposes. Forward-looking statements are not guarantees of future performance and are subject to risks that could cause actual results to differ materially from conclusions, forecasts or projections expressed in such statements, including, among others, risks related to the Company’s future capital requirements, market and general economic conditions, demand for the Company’s customers’ products, and unforeseen legal or regulatory developments. These and other risks and uncertainties, as well as other information related to the Company, are discussed in the Company’s various public filings at www.sedar.com and www.sec.gov, including in the Company’s interim Management’s Discussion and Analysis of Financial Condition and Results of Operations, the Company’s Annual Report on Form 20-F and subsequent reports on Form 6-K filed with or furnished to (as applicable) the U.S. Securities and Exchange Commission, and the Company’s Annual Information Form filed with the Canadian Securities Administrators. The forward-looking statements contained in this press release are based on various assumptions, many of which involve factors that are beyond the Company’s control. The material assumptions include those related to the following: the Company’s view with respect to its financial condition and prospects; the stability of general economic and market conditions; currency exchange rates and interest rates; the availability of cash for repurchases of outstanding subordinate voting shares under the Bid; the existence of alternative uses for the Company’s cash resources which may be superior to effecting repurchases under the Bid; compliance by third parties with their contractual obligations; and compliance with applicable laws and regulations pertaining to the Bid. While management believes these assumptions to be reasonable under the current circumstances, they may prove to be inaccurate. Except as required by applicable law, the Company disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

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