Mankatha (; transl. Gambling) is a 2011 Indian Tamil-language action thriller film directed by Venkat Prabhu and produced by Dayanidhi Azhagiri's Cloud Nine Movies. The film stars an ensemble cast of Ajith Kumar, Lakshmi Rai, Anjali, Arjun Sarja, Trisha Krishnan, Andrea Jeremiah, Ashwin Kakumanu, Vaibhav Reddy, Premji Amaren, Mahat Raghavendra, Jayaprakash, Aravind Akash and Subbu Panchu. It is the fiftieth film of Ajith as a lead actor and the third and penultimate film of the production studio. The film follows Vinayak, a corrupted ACP in Mumbai, who joins a gang of four who plans on a heist of cricket betting money.

The film was officially announced in August 2010 under the initial official title Mangaatha, however, it underwent a change to Mankatha due to numerology reasons. Principal photography commenced in October 2010. It was shot for the most part in Chennai, the Dharavi slum in Mumbai and Bangkok and wrapped by June 2011. Following speculations regarding the film's release, Sun Pictures acquired the theatrical rights and distributed the film via Radhika's Radaan Mediaworks. The film has music composed by Yuvan Shankar Raja, cinematography handled by Sakthi Saravanan and editing by Praveen K. L.-N. B. Srikanth.

Mankatha released worldwide on 31 August 2011 in theatres to critical acclaim from critics and became the second biggest opening Tamil film after Enthiran at the time of release.