Murder Most Foul is the third of four Miss Marple films made by Metro-Goldwyn-Mayer. Loosely based on the 1952 novel Mrs McGinty's Dead by Agatha Christie, it stars Margaret Rutherford as Miss Jane Marple, Ron Moody as the theatre company director H. Driffold Cosgood, Charles Tingwell as Inspector Craddock, and Stringer Davis (Rutherford's husband) as Mr Stringer. The story is ostensibly based on Christie's novel, but notably changes the action and the characters. Hercule Poirot is replaced by Miss Marple and most of the other characters are not in the novel. Throughout the investigation, Marple quotes from "The Shooting of Dan McGrew".

The film was released in 1964. It was directed by George Pollock, and David Pursall is credited with the adaptation. The music is by Ron Goodwin.

The title is a quotation from Hamlet (I.v.27–28), where the Ghost comments about his own death: "Murder most foul as in the best it is/But this most foul, strange and unnatural."

The third film in the MGM series, this was preceded by Murder She Said and Murder at the Gallop, and followed by Murder Ahoy!, all with Rutherford starring as Miss Marple.