The Dark Knight is a 2008 superhero crime thriller film directed and co-written by Christopher Nolan. Based on the DC Comics character Batman, the film is part of Nolan's Batman film series and a sequel to 2005's Batman Begins. Christian Bale reprises the lead role. The film follows Bruce Wayne/Batman (Bale), District Attorney Harvey Dent/Two-Face (Aaron Eckhart), Assistant D.A. Rachel Dawes (Maggie Gyllenhaal), and Police Commissioner James Gordon (Gary Oldman) and their struggles and journey in combating the new rising threat of a criminal who goes by the name of the "Joker" (Heath Ledger).

Nolan's inspiration for the film was the Joker's comic book debut in 1940, and the 1996 series The Long Halloween, which retold Two-Face's origin. The Dark Knight was filmed primarily in Chicago, as well as in several other locations in the United States, the United Kingdom, and Hong Kong. Nolan used an IMAX camera to film some sequences, including the Joker's first appearance in the film. On January 22, 2008, after he had completed filming The Dark Knight, Heath Ledger died from a toxic combination of prescription drugs, leading to intense attention from the press and moviegoing public. Warner Bros. had initially created a viral marketing campaign for The Dark Knight, developing promotional websites and trailers highlighting screen shots of Ledger as the Joker, but after Ledger's death, the studio refocused its promotional campaign.

The film was released on July 16, 2008 in Australia, on July 18, 2008 in North America, and on July 24, 2008 in the United Kingdom. Before its box office debut in North America, record numbers of advance tickets were sold for The Dark Knight. It was greeted with positive reviews upon release, and became only the second film to earn more than $500 million at the North American box office, setting numerous other records in the process. It is also the fifth highest grossing film worldwide, and the fourth of the only five films to earn more than $1 billion, worldwide. The film received numerous awards nominations and two Academy Awards for Best Sound Editing and Best Supporting Actor for Ledger's performance.