Once a Thief
- Taon: 1950
- Bansa: United States of America
- Genre: Crime, Drama
- Studio: W. Lee Wilder Productions
- Keyword: con man, film noir, shoplifting
- Direktor: W. Lee Wilder
- Cast: Cesar Romero, June Havoc, Marie McDonald, Lon Chaney Jr., Iris Adrian, Jack Daley