Strait-Jacket is a 1964 American psychological horror film directed and produced by William Castle, written by Robert Bloch and starring Joan Crawford. Its plot follows a woman who, having murdered her husband and his lover 20 years prior, is suspected of a series of axe murders following her release from a psychiatric hospital.
Released by Columbia Pictures in January 1964, the film was the first of two written for Castle by Bloch, the second being The Night Walker (1964). It was promoted with the tagline "Keep saying to yourself - It's only a film... It's only a film... It's only a film...".