Odd Man Out is a 1947 British film noir directed by Carol Reed, and starring James Mason, Robert Newton, Cyril Cusack, and Kathleen Ryan. Set in Belfast, Northern Ireland, it follows a wounded Nationalist leader who attempts to evade police in the aftermath of a robbery. It is based on the 1945 novel of the same name by F. L. Green.The film received the first BAFTA Award for Best British Film, and was also nominated for the Academy Award for Best Film Editing. Filmmaker Roman Polanski repeatedly cited Odd Man Out as his favourite film.

Odd Man Out follows the Mason character "on an anguished journey through the alleys of Belfast that visually presages Harry Lime's shadowy flight through the sewers of Vienna" in Reed's 1949 film The Third Man.