The Thirteenth Hour is a 1927 American silent mystery film produced and distributed by Metro Goldwyn Mayer and directed by Chester Franklin. The film stars Lionel Barrymore in a role where, as noted criminologist Professor Leroy, he dons a weird series of disguises to hide a dark secret. This was the first film where Barrymore was cast opposite talented dogs, and the first where he was cast as a serial killer.

Lionel Barrymore was an American actor of stage, screen and radio as well as a film director. He won an Academy Award for Best Actor for his performance in A Free Soul (1931), and is known to modern audiences for the role of villainous Mr. Potter in Frank Capra's 1946 film It's a Wonderful Life.