Prince of the City is a 1981 American neo-noir crime drama film directed by Sidney Lumet. It is based on the life of Robert Leuci, called ‘Daniel Ciello’ in the film, an officer of the New York Police Department who chooses, for idealistic reasons, to expose corruption in the force. The screenplay, written by Lumet and Jay Presson Allen, is based on a 1978 non-fiction book of the same title, by former NYPD Deputy Commissioner Robert Daley.

The film stars Treat Williams as Ciello, with a supporting cast featuring Jerry Orbach, Lindsay Crouse and Bob Balaban. Lumet had previously directed Serpico (1973), an award-winning film about corruption in the NYPD. In real life, that film’s subject Frank Serpico was acquainted with Leuci and helped convince him to come forward.

Produced by Orion Pictures and distributed by Warner Bros., the film premiered on August 19, 1981. It received mixed-to-positive reviews from critics and was not a commercial success, but earned several accolades, including an Oscar nomination for Best Adapted Screenplay, and Golden Globe nominations for Best Motion Picture, Best Director for Lumet, and Best Actor for Treat Williams. It also earned the Pasinetti Prize at the 38th Venice International Film Festival.