Day the World Ended is a 1955 independently made black-and-white post-apocalyptic science fiction film, produced and directed by Roger Corman, that stars Richard Denning, Lori Nelson, Adele Jergens, Paul Birch and Mike Connors. Chet Huntley of NBC, later of The Huntley-Brinkley Report, served as the film's narrator. It was released by American Releasing Corporation (later American International Pictures) as a double feature with The Phantom from 10,000 Leagues.

The film's story centers on a heroic scientist who, with a small band of other survivors, faces off against a radioactive mutation following an atomic war that appears to have destroyed most of human civilization.