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. He also directed several films, wrote scripts, created etchings, sketches, and composed music. He was the eldest child of the actors Maurice Barrymore and Georgie Drew Barrymore, and his two siblings were John and Ethel; these and other family members were part of an acting dynasty. Reluctant to follow his parents' career, Barrymore appeared together with his grandmother Louisa Lane Drew in a stage production of The Rivals at the age of 15. He soon found success on stage in character roles. Although he took a break from acting in 1906–1909 to train in Paris as a painter, he was not successful as an artist, and returned to the US and acting. He also joined his family troupe, from 1910, in their vaudeville act.