UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): March 23, 2017

SiteOne Landscape Supply, Inc.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (470) 277-7000

Not Applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Appointment of New Director

Effective as of March 23, 2017, the Board of Directors (the “Board”) of SiteOne Landscape Supply, Inc. (the “Company”) increased the number of directors serving on the Board from nine to ten and filled the vacancy created by such newly-created directorship by appointing Michael J. Grebe. Mr. Grebe will serve as a Class I Director for a term expiring at the Company’s 2017 annual stockholders meeting. The Board also appointed Mr. Grebe to serve on the Audit Committee of the Board, effective as of April 28, 2017. The Board determined, after considering all of the relevant facts and circumstances, that Mr. Grebe is “independent” as defined under New York Stock Exchange (“NYSE”) listing standards.

No arrangements exist between the Company and Mr. Grebe or any other person pursuant to which he was selected as director. There are no transactions in which Mr. Grebe has an interest requiring disclosure under Item 404(a) of SEC Regulation S-K.

Mr. Grebe will be entitled to participate in the Company’s non-employee director compensation plan and certain indemnification rights. Such director compensation plan and indemnification rights are described in more detail under “Executive Compensation-Director Compensation” and “Description of Capital Stock-Limitations on Liability and Indemnification,” respectively, in the final prospectus filed by the Company with the U.S. Securities and Exchange Commission on November 30, 2016 pursuant to Rule 424(b)(4) under the Securities Act of 1933, as amended (Registration No. 333- 214628).

Audit Committee of the Board Member Resignation and Appointment

In connection with Mr. Grebe’s appointment to the Audit Committee of the Board, Kenneth A. Giuriceo resigned as a member of the Audit Committee of the Board, effective as of April 28, 2017. Following Mr. Giuriceo’s resignation and Mr. Grebe’s appointment, the Audit Committee of the Board will be comprised entirely of directors that the Board has determined are “independent” as defined under NYSE listing standards.

In connection with the appointment of Mr. Grebe to the Company’s Board, the Company issued a press release on March 23, 2017. A copy of the press release is furnished as Exhibit 99.1 to this report.

(d) Exhibits

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 hereunto duly authorized.

Date: March 23, 2017

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