Dementia 13 is a 1963 horror film was written and directed by Francis Ford Coppola, produced by Roger Corman and stars William Campbell, Patrick Magee and Luana Anders..

Although Coppola had been involved in at least two films previously, Dementia 13 served as his first mainstream, directorial effort. The plot follows a scheming young woman, who, after having inadvertently caused the heart attack death of her husband, attempts to have herself written into her rich mother-in-law's will. She pays a surprise visit to her late husband's family castle in Ireland but her plans become permanently interrupted by an axe-wielding lunatic who begins to stalk and murderously hack away at members of the family.

Corman offered Coppola the chance to direct a low-budget horror movie in Ireland with funds left over from Corman's recently completed The Young Racers on which Coppola had worked as a sound technician. The producer wanted a cheap Psycho-copy, complete with gothic atmosphere and brutal killings and Coppola quickly wrote a screenplay in accordance with Corman's requirements. Although he was given total directorial freedom during production, Corman eventually brought in another director, Jack Hill, to film additional sequences.