Report of Foreign Issuer (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

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of November, 2018

Commission File Number 001-36487

Atlantica Yield plc

(Exact name of Registrant as Specified in its Charter)

Not Applicable

(Translation of Registrant’s name into English)

Great West House, GW1, 17th floor

Great West Road

Brentford, TW8 9DF

United Kingdom

Tel.: +44 20 7098 4384

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

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): ☐

This Report on Form 6-K is incorporated by reference into each of the Registration Statements on Form F-3 of the Registrant filed with the Securities and Exchange Commission on February 27, 2017 (File No. 333-216253) and August 6, 2018 (File 333-226611).

On November 27, 2018 Algonquin Power & Utilities Corp. (“Algonquin”) announced that they completed the purchase of a 16.5% equity interest in Atlantica Yield (“Atlantica”, NASDAQ: AY) . With this purchase, Algonquin’s total equity interest in Atlantica is now 41.5%.

About Atlantica Yield

Atlantica Yield is a total return company that owns a diversified portfolio of contracted renewable energy, power generation and electric transmission assets in North America, South America and certain markets in EMEA (Spain, Algeria and South Africa). We focus on providing a predictable and growing quarterly dividend or yield to our shareholders (www.atlanticayield.com).

Chief Financial Officer

Francisco Martinez-Davis

E-mail: ir@atlanticayield.com

Investor Relations & Communication

Leire Perez

Tel: +44 20 3499 0465

E-mail: ir@atlanticayield.com

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.