Thaanaa Serndha Koottam (transl.  A Crowd That Gathered on Its Own) is a 2018 Indian Tamil-language crime comedy film directed by Vignesh Shivan. The film stars Suriya, alongside Karthik, Ramya Krishnan, Keerthy Suresh, Nandha, Kalaiyarasan, RJ Balaji, and Suresh Chandra Menon. The film's music was composed by Anirudh Ravichander and the cinematography was performed by Dinesh B. Krishnan and edited by A. Sreekar Prasad. It is a remake of the 2013 Hindi film Special 26, which was inspired by the true event of the 1987 Opera House heist in Mumbai.

The principal photography of the film commenced in September 2016 and ended in August 2017. Thaana Serndha Kootam had a worldwide theatrical release on 12 January 2018. It received generally positive reviews from critics and the audience with praise for the performances of the cast (especially Suriya and Karthik), writing, direction, screenplay, social message, background score, and soundtrack.