Fahrenheit 9/11 is a 2004 documentary film by American filmmaker and political commentator Michael Moore. The film takes a critical look at the presidency of George W. Bush, the War on Terror, and its coverage in the news media. The film holds the record for highest box office receipts by a general release political film. It is the highest grossing documentary of all time domestically.

In the film, Moore contends that American corporate media were "cheerleaders" for the 2003 invasion of Iraq and did not provide an accurate or objective analysis of the rationale for the war or the resulting casualties there. The film's attack on the Bush administration generated some controversy at the time of the film's release, including some disputes over its accuracy. Moore has responded by documenting his sources.

The film debuted at the 2004 Cannes Film Festival in the documentary film category and received a 20 minute standing ovation, among the longest standing ovations in the festival's history. The film was also awarded the Palme d'Or (Golden Palm), the festival's highest award.

The film had a general release in the United States and Canada on June 23, 2004. It has since been released in 42 more countries. By January 2005, the film had grossed nearly $120 million in U.S. box office and over $220 million worldwide, an unprecedented amount for a political film. Sony reported first-day DVD sales of two million copies, again a new record for the genre.

The title of the film alludes to Ray Bradbury's 1953 novel Fahrenheit 451, a dystopian view of the future United States, analogizing the autoignition temperature of paper with the date of the September 11 attacks; the film's tagline is "The Temperature at Which Freedom Burns."