Fiend Without a Face is a 1958 independently made British black-and-white science fiction-horror film drama directed by Arthur Crabtree, and starring Marshall Thompson, Kynaston Reeves, Michael Balfour, and Kim Parker.

It was produced by John Croydon and Richard Gordon for Amalgamated Productions. The screenplay by Herbert J. Leder was based upon Amelia Reynolds Long's 1930 short story "The Thought Monster", originally published in the March 1930 issue of Weird Tales magazine. The film was released in the U.K. by Eros Films; in the U.S. it was released in June 1958 by MGM as a double feature with The Haunted Strangler (1958).

A scientist on an air base in Canada experiments with the materialisation of thought waves through atomic energy, which ultimately take the form of malevolent invisible killer brains, which then materialize as flying brains with attached spinal columns and eyestalks, strangling people with their spinal cords.