UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the
Securities Exchange Act of 1934 (Amendment No.      )

Filed by the Registrant                                      x

Filed by a Party other than the Registrant      ¨

Check the appropriate box:

¨ Preliminary Proxy Statement

¨ Confidential, for use of the Commission only (as permitted by Rule 14A-6(E)(2))

¨ Definitive Proxy Statement

x Definitive Additional Materials

¨ Soliciting Material Pursuant to Section 240.14a-12

SiteOne Landscape Supply, Inc.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

x No fee required.

¨ Fee paid previously with preliminary materials.

¨ Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a6(i)(1) and 0-11

Your Vote Counts! SITEONE LANDSCAPE SUPPLY, INC. 2022 Annual Meeting Vote by May 10, 2022 11:59 PM ETYou invested in SITEONE LANDSCAPE SUPPLY, INC. and it 's time to vote! You have the right to vote on proposals being presented at the Annual Meeting. This is an important notice regarding the availability of proxy material for the shareholder meeting to be held on May 11, 2022.Get informed before you vote View the Notice & Proxy Statement, For m 10-K online OR you can receive a free paper or email copy of the material(s) by request ing prior to April 27, 2022. If you would like to request a copy of the material(s) fo r thi s and/or future shareholde r meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579 -1639 or (3) send an email to sendmaterial@proxyvot e.com. If send ing an email, please include your control number (indicated below) in the sub ject line. Unlessrequested , you will not otherwise receive a paper or email copy.f"1i;l For complete information and to vote, visit www.ProxyVote.com M!!!!!!IIIIL ControI #Smartphone users Poi nt your camera here and vote without entering a ol u mbe,Virtua lly at:Vote Virtually at the Meeting* May 11, 2022 9:00 AM EDTwww .virtualshareholdermeeting.com/S1TE2022*If you choo se to vote these shares in person at the meet ing, you must request a "l egal proxy." To do so, please fo llow the instructions at www .Pro xyVote.com or request a pap er copy of the materials, which will contain the appropriate inst ructions. Please check th e mee t ing m aterials for any special requirements for meet ing attendance .

Vote at www.ProxyVote.comTHIS IS NOT A VOTABLE BALLOT This is an overview of the proposalsbeing presented at the upcoming shareholder meeting. Please follow the instructions on the reverse side to vote theseimportant matte rs.SITEONE LANDSCAPE SUPPLY, INC. 2022 Annual Meeting Vote by May 10, 2022 11:59 PM ETVoting Items 1. Election of Directors Nominees: 01) Fred Diaz 02) Roy Dunbar 03) Larisa Drake 2. Ratif ication of the appointment of Deloitt e & Touche LLP as the company 's independent registered public accounting firm for the year endi ng January 1, 2023.Board Recommends$ For$ For3. Advisory vote to ap prove executive compensat ion . $ For NOTE: Such ot her business as may properly come before the meeting or any adjournment thereof.