Ace in the Hole, also known as The Big Carnival, is a 1951 American comedy-drama film directed by Billy Wilder. The film stars Kirk Douglas as a cynical, disgraced reporter who stops at nothing to try to regain a job on a major newspaper. The film co-stars Jan Sterling and features Robert Arthur and Porter Hall.It marked a series of firsts for auteur Billy Wilder: it was the first time he was involved in a project as a writer, producer, and director; his first film following his breakup with long-time writing partner Charles Brackett, with whom he had collaborated on The Lost Weekend and Sunset Boulevard, among others; and his first film to be a critical and commercial failure.The story is a biting examination of the seedy relationship between the press, the news it reports and the manner in which it reports it. The film also shows how a gullible public can be manipulated by the press. Without consulting Wilder, Paramount Pictures executive Y. Frank Freeman changed the title to The Big Carnival just prior to its release. Early television broadcasts retained that title, but when aired by Turner Classic Movies – and when released on DVD by The Criterion Collection in July 2007 – it reverted to Ace in the Hole.

In 2017, 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 is sometimes referred to as a film noir, but others say that although it shares some qualities with noir, it is not true film noir.