The Ape is a 1940 American horror film directed by William Nigh. The film is based on Adam Hull Shirk's play The Ape, which was previously adapted by Nigh as The House of Mystery (1934). The film stars Boris Karloff as Dr. Bernard Adrian who is seeking to cure a young woman's polio through experiments involving spinal fluid. Meanwhile, a vicious ape has been terrorising the towns locals, and breaking into Adrian's lab. A battle ensues between the two, leading to Adrian deciding to skin the ape and disguise himself as the beast in order to get more spinal fluid. His previous samples were destroyed in the battle.

The Ape was made by Monogram Pictures Corp. after making several Mr. Wong films with both Karloff and Nigh. According to actress Maris Wrixon, it was filmed within a week. The film received mixed reviews from critics on its release, with positive reviews from The Hollywood Reporter, Kinematograph Weekly, and the Los Angeles Times while receiving negative reviews from The New York Times and Variety. Retrospective reviews generally have commented on how ridiculous they had found the film or how a reviewer felt it did not work as a thrilling story.