Underworld U.S.A. is a 1961 American neo-noir crime film produced, written, and directed by Samuel Fuller. It tells the story of a 14-year-old boy who goes to enormous lengths to get revenge against the mobsters who beat his father to death. It stars Cliff Robertson, Dolores Dorn, and Beatrice Kay.

Crime films, in the broadest sense, is a film genre inspired by and analogous to the crime fiction literary genre. Films of this genre generally involve various aspects of crime and its detection. Stylistically, the genre may overlap and combine with many other genres, such as drama or gangster film, but also include comedy, and, in turn, is divided into many sub-genres, such as mystery, suspense or noir.