- The poster for "The Fatties" behind Jeff Portnoy (Jack Black) in the trailer features the names of a few of the film's actual crew members: costume designer Marlene Stewart, editor Greg Hayden, director of photography John Toll, and screenwriter Justin Theroux. In addition, the poster contains the DreamWorks Pictures logo, the Dolby Stereo logo, and a fictional composite of several MPAA ratings (reading "PG - Parental Guidance - under 11 requires accompanying parent or guardian").
- The title is a play on "Tropic Lightning", the nickname of the 25th Infantry Division which has seen action in WWII, Korea, Vietnam, Southwest Asia and Iraq (among others). The Division is notable for being the subject of The Thin Red Line (1998) (based on James Jones's novel) and Platoon (1986). Famous members include Oliver Stone (who wrote and directed "Platoon"), rapper Ice-T and Alaskan Governor Sarah Palin's eldest son.
- Jeff "Fats" Portnoy was written with Jack Black in mind and is partially based on Chris Farley.
- Like his character, Kirk Lazarus, Robert Downey Jr. is a method actor and stayed in character as Sgt. Osiris (and, by extension, Lazarus) even while cameras weren't rolling.
- While filming, Jay Baruchel and Brandon T. Jackson had to be trained on how to use a gun. Jack Black used an M-60, also known as "The Pig." According to his co-stars, he seemed very experienced, despite never having used a gun before.
- The movie drew criticism from several disability groups for the "Simple Jack" subplot, regarding a movie-within-a-movie in which Stiller's character portrays a mentally disabled man. Clips of the fictitious movie are shown, and re-enacted by Stiller, while scenes between Downey Jr. and Stiller drew particular scorn for their repeated use of the word "retard". The producers withdrew a "Simple Jack" website, and proposed altering the movie in response to a special early screening for the disability groups in question, but did not follow through on the suggestion. According to co-writer Etan Cohen, the scenes were not meant to derive humor from mental disability itself, but to satirize emotionally exploitative depictions of mental disability in movies such as Forrest Gump (1994), I Am Sam (2001), Radio (2003), and Rain Man (1988), and the actors who take these roles.
- The character of Kirk Lazarus (Robert Downey Jr.) was originally written as Irish. It was changed to Australian, when Robert Downey Jr. said it would be easier for him to improvise in an Australian accent - something he'd done with his character, Wayne Gale, in Natural Born Killers (1994).
- Downey was very reluctant to take the role because he felt wearing the make-up to look African-American was offensive. But Downey later accepted the role because he liked the script and wanted to work with Stiller and Jack Black.
- According to Ben Stiller, in an interview with Playboy, Jack Black filmed most of this movie with bruised ribs.
- Shipped to some theaters under the name "Capricorn".
- In the film, Kirk Lazarus says "I don't drop character 'til I've done the DVD commentary." When recording the audio commentary for the unrated DVD and blu-ray, Robert Downey Jr. actually spends the entire commentary in the character that appears on the screen as the movie progresses.
- In one of the special features on the director's cut DVD, Ben Stiller said he has been developing ideas for this movie for about 8-10 years. One of his first ideas was that the movie was going to be about actors going to a "fake boot camp" for a couple of weeks and coming back with Post Traumatic Stress Disorder. When Stiller started out in Hollywood, he had a lot of colleagues going into war movies and they would attend a "fake boot camp" in order to prepare for their roles. He found it ridiculous and this was an early inspiration on what would become "Tropic Thunder".
- Cameo: [Justin Theroux] the gunner on one of the Hueys in the beginning of the film, and the Zoolander (2001) DJ at the One Week Down party in the director's cut.
- At 00:06:30, the shriek of an Alien (1979) dying is audible.
- Tom Cruise co-stars as a vulgar movie mogul in this movie. Ben Stiller played Cruise in a sketch on Saturday Night Live in which Cruise played "Celebrity Jeopardy" and also played Cruise's idiotic stunt double "Tom Croose" in a sketch at the 2000 MTV movie awards.
- Several actors and actresses make cameo appearances in the movie, including Tobey Maguire, Jennifer Love Hewitt, Lance Bass, Jon Voight and Jason Bateman.
- The Flo Rida hit "Low" played on the cell phone by Les Grossman was added during post-production, when the song became a radio hit.
- In his 'full-blown retard' Oscar monologue, Kirk cites Peter Sellers' performance in Being There (1979). While Sellers received a Golden Globe award, he did not win the Best Actor Oscar that year, which went to Dustin Hoffman for Kramer vs. Kramer (1979).
- Many have speculated that Tom Cruise based his performance as a vulgar movie mogul on Sumner Redstone, with whom Cruise had a public falling out after Redstone had Paramount's terminate their development deal with Cruise. While this may or may not be true, his physical appearance is more than likely based on "Tropic Thunder" producer Stuart Cornfeld.
- There are several scenes that intentionally mock and resemble certain moments in other movies. Examples include Sandusky's internal organs protruding out of his body (mocking Saving Private Ryan (1998)), Speedman kneeling and holding his arms up while being shot (mocking Platoon (1986)), and Speedman being thrown in two directions from the bridge explosion (mocking Mission: Impossible III (2006)).
- In the film, Damien's surname "Cockburn" is pronounced phonetically (probably for humorous effect), whereas it is properly pronounced "Coh-burn".
- According to Ben Stiller, Tugg Speedman is partially based on a young Sylvester Stallone.
- According to Robert Downey Jr., Kirk Lazarus is based on a combination of Russell Crowe, Daniel Day-Lewis, and Colin Farrell.
- Despite being a war movie, there is only one death that occurs.
>>> WARNING: Here Be Spoilers <<<
Trivia items below here contain information that may give away important plot points. You may not want to read any further if you've not already seen this title.
- SPOILER: [WILHELM SCREAM] During the three-helicopter raid at the beginning of the film, when an enemy soldier is hit by gunfire and is blown backwards (elapsed time 6:04). Also, when Tugg Speedman throws "Half-squat" into the river in the finale. When this throw is repeated in the end credits, the scream is heard again.
- SPOILER: Jon Voight's character is visibly angry when loses the Oscar to Tugg at the film's end. This is a reference to Voight losing the Oscar to John Wayne in True Grit (1969) when he was nominated for Midnight Cowboy (1969).
- SPOILER: Tug Speedman's celebration leap while holding his Oscar spoofs a similar antic by Cuba Gooding Jr. after he won for Jerry McGuire. Tug's leap can be seen on the TV screen behind Les Goodman when Goodman is gyrating at the end.
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