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 November 2025

Eni S.p.A.

(Exact name of Registrant as specified in its charter)

Piazzale Enrico Mattei 1 - 00144 Rome, Italy

(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 whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2b 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): ____)

TABLE OF CONTENTS

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, hereunto duly authorised.

Date: November 26, 2025

Eni: report on the purchase of treasury shares on 17 November 2025

San Donato Milanese (Milan), 26 November 2025 – On 17 November 2025, Eni acquired on the Euronext Milan no. 604,654 shares (equal to 0.02% of the share capital), at a weighted average price per share equal to 16.5384 euro, for a total consideration of 9,999,987.34 euro within the treasury shares program approved by the Shareholders' Meeting on 14 May 2025, previously subject to disclosure in accordance with applicable legislation.

From the start on 20 May 2025 of the buyback program, Eni acquired no. 81,621,823 shares (equal to 2.59% of the share capital) for a total consideration of 1,190,047,828.22 euro.

Considering the treasury shares already held and the purchases made and the free of charge shares granted to Eni’s executives, following the conclusion of the Vesting Period as provided by the “Long-Term Incentive Plan 2020-2022” approved by Eni’s Shareholders’ Meeting of 13 May 2020, Eni holds n. 171,739,182 shares equal to 5.46% of the share capital.

Details of the daily transactions made on 17 November 2025 are reported below.

Eni Company Contacts:

Press Office: Tel. +39.0252031875 – +39.0659822030

Freephone for shareholders (from Italy): 800940924
Freephone for shareholders (from abroad): +39.800 11 22 34 56

Switchboard: +39.0659821

ufficio.stampa@eni.com

segreteriasocietaria.azionisti@eni.com

investor.relations@eni.com

Website: www.eni.com