The Man Who Knew Too Much is a 1934 British spy thriller film directed by Alfred Hitchcock, featuring Leslie Banks and Peter Lorre, and released by Gaumont British. It was one of the most successful and critically acclaimed films of Hitchcock's British period.

The film is Hitchcock's first film using this title and was followed later with his own 1956 film using the same name featuring a significantly different plot and script with some modifications. The second film featured James Stewart and Doris Day, and was made for Paramount Pictures. The two films are very similar in tone. In the book-length interview Hitchcock/Truffaut (1967), in response to filmmaker François Truffaut's assertion that aspects of the remake were by far superior, Hitchcock replied, "Let's say the first version is the work of a talented amateur and the second was made by a professional." However, some critics have concluded that Hitchcock's statement should not be taken at face value.

The 1934 film has nothing except the title in common with G. K. Chesterton's 1922 book of the same name. Hitchcock decided to use the title because he held the film rights for some of the stories in the book.