Thunivu (transl. Fortitude, also marketed as Thunivu – No Guts No Glory) is a 2023 Indian Tamil-language action thriller film written and directed by H. Vinoth, and produced by Boney Kapoor under Bayview Projects LLP and Zee Studios. The film stars Ajith Kumar, alongside Manju Warrier, Samuthirakani, John Kokken, Ajay and Veera. It follows Dark Devil and his team who forms a plan and commits bank heist to find the corporate looted people's money.

The film was officially announced in February 2022 under the tentative title AK61, as it is Ajith's 61st film in a leading role, and the official title was announced in September 2022. Principal photography commenced in April 2022 in Hyderabad along with a schedule in Chennai, which was followed up with a sporadic schedule in Thailand, and wrapped by late-November 2022. The film has music composed by Ghibran, cinematography handled by Nirav Shah and Vijay Velukutty.

Thunivu was released theatrically in the week of Pongal on 11 January 2023. It received mixed reviews from critics.