Tropic Thunder is a 2008 American action comedy film directed and produced by Ben Stiller and written by Stiller, Justin Theroux, and Etan Cohen. The film stars Stiller, Jack Black and Robert Downey Jr. as a group of prima donna actors making a Vietnam War film when their fed-up writer and director decides to abandon them in the middle of the Vietnamese jungle, forcing them to fight their way out.

Stiller initially had the idea for the film while playing a small part in Empire of the Sun (1987) and later brought on Theroux and Cohen to help him complete the script. After the film was greenlit in 2006, filming took place in 2007 on the Hawaiian island of Kauai over 13 weeks and was later deemed the largest film production in the island's history. Tropic Thunder had a massive marketing promotion, including posting faux websites for the characters, fake films, and products shown within the film; showing numerous screenings; and selling the fictional energy drink advertised in the film.

Released in the United States on August 13, 2008, it received generally good reviews with 83% of reviews positive and an average normalized score of 71% according to the review aggregator websites Rotten Tomatoes and Metacritic, respectively. It earned $26 million in its opening weekend and retained the number-one position for its first three consecutive weekends of release. The film went on to gross more than $180 million worldwide before its release on home video on November 18, 2008.