X, better known by its promotional title, X: The Man with the X-ray Eyes, is a 1963 American science fiction horror film in Pathécolor, produced and directed by Roger Corman, from a script by Ray Russell and Robert Dillon. The film stars Ray Milland as a scientist who develops a method to extend the range of his vision, which results in unexpected complications. Comedian Don Rickles co-stars in one of his few dramatic roles. Diana Van der Vlis and veteran character actor Morris Ankrum also make appearances.

American International Pictures distributed the film in the fall of 1963 as a double feature with Francis Ford Coppola's horror thriller Dementia 13. The low-budget film was a major financial success.