United 93 is a 2006 docudrama thriller film written and directed by Paul Greengrass. The film largely chronicles the events aboard United Airlines Flight 93, one of the four hijacked flights during the September 11 attacks and the only one not to hit its intended target due to the intervention of passengers and crew; it also covers the experiences of government officials and air traffic controllers watching the other events of the attacks unfold.

The film attempts to recount the hijacking and subsequent events in the flight with as much veracity as possible (there is a disclaimer that some imagination had to be used) and in real time (from the flight's takeoff). The film was made with the cooperation of many of the passengers' families, though not all agreed to participate; many also attended the premiere. Furthermore, many of the on-the-ground personnel, most notably Federal Aviation Administration head Ben Sliney, portray themselves.

United 93 premiered on April 26, 2006, at the Tribeca Film Festival in New York City, and later opened in North America on April 28, 2006. The film is regarded as one of the best films of 2006. It was also a commercial success, grossing $76.3 million worldwide. Ten percent of the gross income from the three-day opening weekend was promised toward a donation to create a memorial for the flight's victims. The film also received two Academy Award nominations, including Best Director for Greengrass.