Once a Thief
- An: 1950
- Pays: United States of America
- Genre: Crime, Drame
- Studio: W. Lee Wilder Productions
- Mot-clé: con man, film noir, shoplifting
- Réalisateur: W. Lee Wilder
- Jeter: Cesar Romero, June Havoc, Marie McDonald, Lon Chaney Jr., Iris Adrian, Jack Daley