Big B (short form of Big Brother) is a 2007 Indian Malayalam-language neo-noir action thriller film directed by Amal Neerad in his directoral debut. It stars Mammootty, Manoj K. Jayan, Bala and Sumit Naval. The cinematography and editing were handled by Sameer Thahir and Vivek Harshan, while the music was composed by Alphonse Joseph and Gopi Sundar.

Despite being an unofficial remake of the 2005 Hollywood film Four Brothers, Big B is considered a pathbreaking film in the history of Malayalam cinema due to its stylish making and also introduced a new style of filmmaking, thus attaining a huge cult following. The film is widely regarded as one of the defining films of the Malayalam New Wave.