Spider Baby: or, the Maddest Story Ever Told is a 1967 American comedy horror film, written and directed by Jack Hill. It stars Lon Chaney Jr. as Bruno, the chauffeur and caretaker of three orphaned siblings who suffer from "Merrye Syndrome", a genetic condition starting in early puberty that causes them to regress mentally, socially and physically. Jill Banner, Carol Ohmart, Quinn Redeker, Beverly Washburn, Sid Haig, Mary Mitchel, Karl Schanzer and Mantan Moreland also star.

The film was released to relative obscurity, but eventually achieved cult status.