Report of Foreign Issuer Pursuant to Rule 13a-16 or 15d-16 (6-k)

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

Report of Foreign Issuer

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

of the Securities Exchange Act of 1934

For the month of March 2022

Commission File Number: 001-35052

Adecoagro S.A.

(Translation of registrant’s name into English)

Vertigo Naos Building 6,

Rue Eugene Ruppert,

L-2453, Luxembourg

Grand Duchy of Luxembourg

(Address of principal executive offices)

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 x 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):

Yes ¨ No x

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):

Yes ¨ No x

Indicate by check mark whether by furnishing the information contained in this Form, the Registrant is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934:

Yes ¨ No x

If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): N/A

AUDITED CONSOLIDATED FINANCIAL STATEMENTS AS OF DECEMBER 31, 2021 AND 2020 AND

FOR THE YEARS ENDED DECEMBER 31, 2021, 2020 AND 2019

This Report of Foreign Private Issuer on Form 6-K (this “Form 6-K”) is being furnished by Adecoagro S.A. (“Adecoagro” or the “Company”) with the Securities and Exchange Commission (the “SEC”). The Company is furnishing this report on Form 6-K for the purpose of furnishing a copy of the Company’s audited consolidated financial statements as of December 31, 2021 and 2020 and for the years ended December 31, 2021, 2020 and 2019 (the “Consolidated Financial Statements”) as Exhibit 99.1. The Consolidated Financial Statements are presented in U.S. Dollars and prepared in accordance with International Financial Reporting Standards as issued by the International Accounting Standards Board.

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.