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 May 2026

Commission File Number 0001002242

Eni S.p.A.

(Translation of registrant’s name into English)

Piazzale Enrico Mattei 1 - 00144 Rome, Italy

(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.

X Form 20-F               ☐ Form 40-F

TABLE OF CONTENTS

SIGNATURE

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.

Eni: report on the purchase of treasury shares on 8 May 2026

San Donato Milanese (Milan), 13 May 2026 – On 8 May 2026, Eni acquired on the Euronext Milan no. 875,813 shares (equal to 0.03% of the share capital), at a weighted average price per share equal to 22.8359 euro, for a total consideration of 19,999,978.09 euro, within the first tranche of the treasury shares program approved by the Shareholders' Meeting on 6 May 2026, for the purpose of serving the 2026-2028 Long-Term Incentive Plan, resolved by the same Shareholders’ Meeting.

Considering the treasury shares already held and the purchases made, Eni holds n. 87,703,920 shares equal to 2.90% of the share capital.

Details of the hourly transactions made during 8 May.