6-K

UNITEDSTATES

SECURITIESAND EXCHANGE COMMISSION

WASHINGTON,DC 20549

FORM6-K

REPORTOF FOREIGN PRIVATE ISSUER

PURSUANTTO RULE 13a-16 OR 15d-16

OFTHE SECURITIES EXCHANGE ACT OF 1934

Forthe month of October 2025

CommissionFile Number: 001-41782

VinFastAuto Ltd.

DinhVu – Cat Hai Economic Zone

CatHai Island, Cat Hai Special Zone

HaiPhong City, Vietnam

(Addressof 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. Form 20-F ☒     Form 40-F ☐

INFORMATIONCONTAINED IN THIS REPORT ON FORM 6-K

VINFASTREPORTS RECORD DELIVERIES, SURPASSING 100,000 ELECTRIC VEHICLES IN THE FIRST NINE MONTHS OF 2025 IN VIETNAM

Hanoi,October 14, 2025 – VinFast Auto Ltd. (“VinFast” or the “Company”) announced its preliminary domesticVietnam deliveries of 13,914 electric vehicles (“EVs”)^1^ in September 2025. Cumulatively, during the first ninemonths of 2025, the Company delivered a total of 103,884 EVs^1^ to customers in Vietnam. This milestone marks the first timean automaker in Vietnam has delivered more than 100,000 vehicles^2^ in the first three quarters of a year, underscoring VinFast’smarket leadership and continued growth momentum.

Notably, 3,847 VF 5 vehicles^1^ were delivered in September 2025, making it VinFast’s best-selling model for the month. The VF 3 ranked second, with 2,682 vehicles^1^ delivered. The Herio Green ranked third with 2,173 vehicles^1^ delivered, followed by the Limo Green with 2,120 vehicles^1^, the VF 6 with 1,933 vehicles^1^ and the VF 7 with 778 vehicles^1^.

For the first nine months of 2025, the VF 3 and the VF 5 were VinFast’s two best-selling models in Vietnam with cumulative deliveries of 31,386 and 30,956 vehicles^1^, respectively. The Company also delivered 14,425 VF 6 vehicles^1^, 8,604 Herio Green vehicles^1^ and 5,877 VF 7 vehicles^1^ during the period.

This Form 6-K shall be deemed to be incorporated by reference into the Company’s registration statement on Form S-8 (File No. 333-278251) and registration statement on Form F-3 (File No. 333-275133) (including any prospectuses forming a part of such registration statements) and to be a part thereof from the date on which this report is furnished, to the extent not superseded by documents or reports subsequently filed or furnished.

Note1: Preliminary delivery results are subject to change and may differ from the final number of deliveries that will be recognized as vehiclesales revenue for the period as a result of the year end audit.

Note2: Market and industry statements in this document are based on data from the Vietnam Automobile Manufacturers’ Association andCompany internal data (for VinFast only).

AboutVinFast

VinFast(NASDAQ: VFS) – a subsidiary of Vingroup JSC – is Vietnam’s leading automotive manufacturer, committed to its missionof creating a green future for everyone. VinFast produces a range of electric SUVs, e-scooters, e-bikes, and e-buses in Vietnam and exportsto key markets across Asia, North America, and Europe. Learn more at www.vinfastauto.us.

VinFastdeliveries represent only one measure of the Company’s financial performance and should not be relied on as an indicator of quarterlyfinancial results, which depend on a variety of factors, including the average selling price and various cost components.

1

SIGNATURE

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.

2