The Lost One (German: Der Verlorene) is a 1951 West German crime drama film directed by Peter Lorre and starring Lorre, Karl John and Renate Mannhardt. It is an art film in the film noir style, based on a true story. Lorre wrote, directed, and starred in this film, his only film as director or writer. The film's translated name has been used as the title of his biography.

The film's sets were designed by the art directors Franz Schroedter and Karl Weber. Some scenes were shot at Studio Bendestorf and on provisional stages in the former flak tower on Heiligengeistfeld Hamburg, while location shooting took place around the city.