6-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

OF THE SECURITIES EXCHANGE ACT OF 1934

For the month of March 2023

Commission File Number: 001-39240

GFL Environmental Inc.

(Translation of registrant’s name intoEnglish)

100 New Park Place, Suite 500

Vaughan, Ontario, Canada L4K 0H9

(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.

Form 20-F ¨              Form 40-F x

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

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

EXHIBIT INDEX

The following exhibit is furnished as part of this Current Report on Form 6-K.

1

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.

2

Exhibit 99.1

GFL Environmental Inc. Announces Settlement of Tangible EquityUnits

VAUGHAN, ON, March 16, 2023 – GFL Environmental Inc. (NYSE: GFL) (TSX: GFL) ("GFL") today announced that it has satisfied its remaining obligations under its 6.00% Tangible Equity Units (“TEUs”) previously issued on March 5, 2020, in connection with its initial public offering.

Effective March 15, 2023, the purchase contracts of each outstanding TEU automatically converted into subordinate voting shares at the minimum settlement rate of 2.1940 plus cash in lieu of fractional shares. See Appendix “A” for the pro forma impact of the conversion of the purchase contracts on the outstanding subordinate voting shares as at December 31, 2022, assuming the conversion took effect as at December 31, 2022.

GFL has also made the final installment payment on the senior amortizing note portion of each TEU in full satisfaction of all principal and interest payments thereunder.

About GFL

GFL, headquartered in Vaughan, Ontario, is the fourth largest diversified environmental services company in North America, providing a comprehensive line of solid waste management, liquid waste management and soil remediation services through its platform of facilities throughout Canada and in more than half of the U.S. states. Across its organization, GFL has a workforce of more than 19,500 employees.

For more information:

Appendix “A”

The following table presents the total shares outstanding as at December 31, 2022 and the pro forma effect of the conversion of the purchase contracts, assuming the conversion thereof as at December 31, 2022: