12 Angry Men is a 1957 American courtroom drama film directed by Sidney Lumet, adapted from a teleplay of the same name by Reginald Rose. This courtroom drama tells the story of a jury of 12 men as they deliberate the conviction or acquittal of a defendant on the basis of reasonable doubt, forcing the jurors to question their morals and values. In the United States, a verdict in most criminal trials by jury must be unanimous. The defendant is an 18-year-old male, and the witnesses are a lady across the street and an old man.

12 Angry Men explores many techniques of consensus-building and the difficulties encountered in the process among this group of men whose range of personalities adds to the intensity and conflict. It also explores the power one person has to elicit change. No names are used in the film; the jury members are identified by number until two members exchange names at the end. The film forces the characters and audience to evaluate their own self-image through observing the personality, experiences, and actions of the jurors. The film is notable for its almost exclusive use of one set. Only three minutes take place that are not set in the jury room.

In 2007, the film was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant". The film was selected as the second-best courtroom drama ever by the American Film Institute during their AFI's 10 Top 10 list.