The Quatermass Xperiment is a 1955 British science fiction horror film from Hammer Film Productions, based on the 1953 BBC Television serial The Quatermass Experiment written by Nigel Kneale. The film was produced by Anthony Hinds, directed by Val Guest, and stars Brian Donlevy as the titular Professor Bernard Quatermass and Richard Wordsworth as the tormented Carroon. Jack Warner, David King-Wood, and Margia Dean appear in co-starring roles.

Professor Bernard Quatermass is a fictional scientist originally created by writer Nigel Kneale for BBC Television. An intelligent and highly moral British scientist, Quatermass is a pioneer of the British space programme, heading the British Experimental Rocket Group. He continually finds himself confronting sinister alien forces that threaten to destroy humanity.