The Werewolf is a 1956 American horror science fiction film directed by Fred F. Sears and starring Don Megowan and Joyce Holden.

Set in contemporary times (i.e. the 1950s), the storyline follows an amnesiac man who, after being injected with "irradiated wolf serum" by unscrupulous doctors, transforms into a werewolf when under emotional stress. The film "marks precisely the point in which horror, which had been a dormant genre in the early '50s, began to take over from science fiction", and is the first of only three werewolf films made in the US during that decade, preceding Daughter of Dr. Jekyll and I Was a Teenage Werewolf (both 1957). The Werewolf was released theatrically in the US as the bottom half of a double feature with Earth vs. the Flying Saucers (1956).