Exhibit 5.1​

Consent of Independent Registered Public Accounting Firm

We hereby consent to the incorporation by reference in this Amendment No. 1 to the Registration Statement (No. 333-255184) on Form F-10 of our report dated February 25, 2021 relating to the financial statements of GFL Environmental Inc. appearing in the Annual Report on Form 20-F for the year ended December 31, 2020.

/s/ Deloitte LLP

Chartered Professional Accounts
Licensed Public Accountants
Toronto, Canada
April 20, 2021