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 April 2025

Commission File Number: 001-40401

Oatly Group AB

(Translation of registrant’s name into English)

Ångfärjekajen 8

211 19 Malmö

Sweden

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

On April 11, 2025, Oatly Group AB (publ) (the “Company”) published its notice convening the annual general meeting of the Company (the “Notice”), which is to be held on May 20, 2025. A copy of the Notice is being furnished as Exhibit 99.1 to this report of foreign private issuer on Form 6-K. Materials relating to the annual general meeting are available on the Company’s website at https://investors.oatly.com/corporate-governance/annual-general-meeting-2025.

EXHIBIT INDEX

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.