The Horse's Mouth is a 1944 novel by Joyce Cary, the third in a trilogy.

The book follows the adventures of Gulley Jimson, an artist who would exploit his friends and acquaintances to earn a quid. Cary's novel also uses Gully's unique perspective to comment on the social and political events of the time.

The book was adapted as a film in 1958, with a Academy Award-nominated screenplay by actor Alec Guinness. The film was directed by Ronald Neame, and starred Guinness, Kay Walsh, Renee Houston , Mike Morgan , and Robert Coote . It generally follows the book, but focuses on the Jimson character and what it means to be an artist, rather than the social and political themes.