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 January, 2026

Commission File Number 001-34175

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 the registrant by furnishing the information contained in this form 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): 82- N/A

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.

Date: January 23, 2026

Update on the VAT proceedings related to fuelimports

Ecopetrol S.A. (BVC: ECOPETROL; NYSE: EC) (the “Company” or “Ecopetrol”) reports that on January 22, 2026, the Colombian National Tax and Customs Authority (“DIAN”) notified Ecopetrol of Resolution 000571 (the “Resolution”), in accordance with its interpretation and customs procedures. By means of this Resolution, DIAN confirmed its prior decision issued in the Official Correction Assessment 6224-2078 dated August 25, 2025, which mandated the payment of certain Value Added Tax (VAT) on gasoline imports and a penalty, which together amount to COP 5.3 trillion, plus interest for late payment, accrued between 2022 and 2024.

As previously communicated, Ecopetrol has expressed its disagreement with DIAN’s decision and interpretation of the laws. Given that such difference in regulatory interpretation between DIAN and the Company remains, Ecopetrol expects to pursue the appropriate legal actions in accordance with current tax and customs regulations.

This legal dispute has been managed in a collaborative manner and within a framework of joint work between the company and the tax authority. Ecopetrol reaffirms its commitment to fully comply with its customs and tax obligations and will respect the decisions issued by the competent authorities in resolving this matter.

Bogota D.C., January 23^rd^, 2025

Ecopetrol is the largest company in Colombia andone of the main integrated energy companies in the American continent, with more than 19,000 employees. In Colombia, it is responsiblefor more than 60% of the hydrocarbon production of most transportation, logistics, and hydrocarbon refining systems, and it holds leadingpositions in the petrochemicals and gas distribution segments. With the acquisition of 51.4% of ISA’s shares, the company participatesin energy transmission, the management of real-time systems (XM), and the Barranquilla - Cartagena coastal highway concession. At theinternational level, Ecopetrol has a stake in strategic basins in the American continent, with Drilling and Exploration operations inthe United States (Permian basin and the Gulf of Mexico), Brazil, and Mexico, and, through ISA and its subsidiaries, Ecopetrol holds leadingpositions in the power transmission business in Brazil, Chile, Peru, and Bolivia, road concessions in Chile, and the telecommunicationssector.

This release contains statements that may be consideredforward-looking statements within the meaning of Section 27A of the U.S. Securities Act of 1933, as amended, and Section 21E of the U.S.Securities Exchange Act of 1934, as amended. All forward-looking statements, whether made in this release or in future filings or pressreleases, or orally, address matters that involve risks and uncertainties, including in respect of the Company’s prospects for growthand its ongoing access to capital to fund the Company’s business plan, among others. Consequently, changes in the following factors,among others, could cause actual results to differ materially from those included in the forward-looking statements: market prices ofoil & gas, our exploration, and production activities, market conditions, applicable regulations, the exchange rate, the Company’scompetitiveness and the performance of Colombia’s economy and industry, to mention a few. We do not intend and do not assume anyobligation to update these forward-looking statements.

For more information, please contact:

Investors Relations Office

Email: investors@ecopetrol.com.co

Head of Corporate Communications (Colombia)

Marcela Ulloa

Email: marcela.ulloa@ecopetrol.com.co