As filed with the Securities and Exchange Commission on May 8, 2014

Registration No. 333-            

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

PATTERN ENERGY GROUP INC.

(Exact Name of Registrant as Specified in Its Charter)

Pier 1, Bay 3

San Francisco, CA 94111

(415) 283-4000

(Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant’s Principal Executive Offices)

Daniel M. Elkort

General Counsel

Pattern Energy Group Inc.

Pier 1, Bay 3

San Francisco, CA 94111

(415) 283-4000

(Name, Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent For Service)

Copies to:

Approximate date of commencement of proposed sale to the public: As soon as practicable after the effective date of this Registration Statement.

If any of the securities being registered on this form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box.  ¨

If this form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  x 333-195488

If this form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ¨             

If this form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ¨             

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

CALCULATION OF REGISTRATION FEE

Incorporation by Reference of Registration Statement on Form S-1, File No. 333-195488

Pattern Energy Group Inc. (the “Company”) hereby incorporates by reference into this Registration Statement on Form S-1 in its entirety the Registration Statement on Form S-1 (File No. 333-195488) declared effective on May 8, 2014 by the Securities and Exchange Commission (the “Commission”), including each of the documents filed by the Company with the Commission and incorporated or deemed to be incorporated by reference therein and all exhibits thereto.

Exhibits

The following documents are filed as exhibits to this Registration Statement.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the registrant has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in San Francisco, California, on this 8^th day of May, 2014.

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed by the following persons in the capacity and on this 8^th day of May, 2014.

EXHIBITS