6-K

FORM 6-K

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

Report of Foreign Private Issuer

Pursuant to Rule 13a - 16 or 15d - 16 of

the Securities Exchange Act of 1934

SUNCOR ENERGY INC.

(Name of registrant)

150 – 6th Avenue S.W.

P.O. Box 2844

Calgary, Alberta

Canada, T2P 3E3

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 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): ¨

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.

EXHIBIT INDEX

EXHIBIT 99.1

News Release dated May 26, 2023, Suncor Energy provides update on acquisition of TotalEnergies’ Canadian operations

FOR IMMEDIATE RELEASE

Suncor Energy provides update on acquisition of TotalEnergies’Canadian operations

Calgary, Alberta (May 26, 2023) – Suncor Energy (TSX: SU) (NYSE: SU) (“Suncor”) announced that it has been notified that ConocoPhillips Canada (“ConocoPhillips”) has elected to exercise their right of first refusal with respect to TotalEnergies’ 50% working interest in the Surmont asset.

Suncor’s agreement to close the transaction to acquire TotalEnergies’ Canadian operations was conditional upon ConocoPhillips waiving its right of first refusal in respect of the Surmont working interest. As a result, each of the parties has the right to terminate the agreement under which Suncor would acquire TotalEnergies’ Canadian operations and Suncor will be assessing the transaction in light of this change.

Suncor is Canada’s leading integrated energy company. Suncor’soperations include oil sands development, production and upgrading, offshore oil and gas production, petroleum refining in Canada andthe United States and the company’s Petro-Canada retail and wholesale distribution networks, including Canada’s ElectricHighway, a coast-to-coast network of fast-charging EV stations. Suncor is developing petroleum resources while advancing the transitionto a low-emissions future through investment in power, renewable fuels and hydrogen. Suncor also conducts energy trading activities focusedprincipally on the marketing and trading of crude oil, natural gas, byproducts, refined products and power. Suncor has been recognizedfor its performance and transparent reporting on the Dow Jones Sustainability index, FTSE4Good and CDP. Suncor’s common shares(symbol: SU) are listed on the Toronto and New York stock exchanges.

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For more information about Suncor, visit our web site at suncor.com or follow us on Twitter @Suncor

Media inquiries:

(833) 296-4570

media@suncor.com

Investor inquiries:

(800) 558-9071

invest@suncor.com