Thief is a 1981 American neo-noir heist film written and directed by Michael Mann in his feature film debut. It stars James Caan as a professional safecracker trying to escape his life of crime, and Tuesday Weld as his wife. The supporting cast includes Jim Belushi, Robert Prosky, Dennis Farina, and Willie Nelson. The screenplay is inspired by the memoir The Home Invaders: Confessions of a Cat Burglar, by former cat burglar Frank Hohimer. The original musical score was composed and performed by Tangerine Dream.

Produced by Jerry Bruckheimer and James Caan's brother Ronnie, Thief was screened at the 1981 Cannes Film Festival, where it competed for the Palme d'Or. It was released in the United States on March 27, 1981, to widespread critical acclaim. Thief earned $11.5 million at the box office, on a $5.5 million budget.