QuickLinks -- Click here to rapidly navigate through this document

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

For the month of: February, 2014

  Commission File Number: 1-12384

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:

Form 20-F

  o   Form 40-F   ý

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.

  SUNCOR ENERGY INC.

Date: February 28, 2014                                                                         

       

 

By:

 

/s/ SHAWN POIRIER


Shawn Poirier
Assistant Corporate Secretary


EXHIBIT INDEX

Exhibit
  Description of Exhibit

99.1

  2013 Annual Report to Shareholders for the period ended December 31, 2013

99.2

  Form NI 51-101F4



QuickLinks

SIGNATURES
EXHIBIT INDEX