Derek's repetition of the line "But why male models?" for the second time, in the cemetery scene, was an ad-lib by the actors; Ben Stiller forgot his line and simply repeated the earlier line again, and David Duchovny ran with it and gave him a straight answer.
The film has been banned in Malaysia because of the use of fictional Malaysian Prime Minister as the subject of assassination. It was originally also banned in neighboring Singapore, but the ban has since been lifted.
Bret Easton Ellis, author of the 1998 novel "Glamorama," about a dimwitted male model who finds himself embroiled in a terrorist ring with roots in the fashion industry, sued Ben Stiller following the release of this film, citing copyright infringement. The case was later settled out of court.
Images of the World Trade Center towers were removed before the movie's September 28, 2001 release, only 17 days after the 9/11 terrorist attacks where the towers were brought down. They were edited out in one shot and obscured in another.
While trying to be farcical, the film is actually quite accurate regarding the modeling industry. Even the quick scene of the two sets of bunk beds at Derek's apartment is factual; Cindy Crawford and Jules Asner shared a similar bunkroom during the early days of their modeling careers.
According to an interview with Ben Stiller, Zoolander started out as a character sketch for VH1 Fashion Awards. After several written scripts and over several years, the studio finally agreed to film Zoolander. The movie's release immediately following September 11th has been cited as a reason for its failure at the box office.
When Derek and Hansel are trying to turn on the computer, the whole scene is a reference to Stanley Kubrick's 2001: A Space Odyssey (1968). (They are acting like monkeys, the same music plays, and Hansel grabs a bone just like in Kubrick's movie.
When Derek first gets to Hansel's pad and Hansel asks Ennui to get him some of the special tea, there is a picture in the background of Hansel holding two tires. This is a copy of a famous Herb Ritts photo from 1984, "Fred with tyres."
Milla Jovovich's character Katinka calls Mathilda "Kmart", in reference to her low fashion clothing from the store. In Jovovich's "Resident Evil" movies, there is a character named "K-Mart" (played by Spencer Locke).
The trivia items below may give away important plot points.
The club scene depicts (cameo) Winona Ryder's character giving Derek Zoolander advice to "lay low" in order to rebuild his modeling career. This scene foreshadowed Ryder's real-life experience with a shipwrecked career. Three months after the release of Zoolander, Ryder would be arrested for shoplifting clothes. Later, she self-imposed a six-year career exile to rebuild her reputation as a serious actress.
Saint Adonis Cemetery, where the three male models are buried after their "freak gasoline fight accident," does not exist; in fact, there is no such saint. Adonis is a young man in ancient Greek mythology known for his great beauty.
In the Hansel apartment scene, Matlida (Christine Taylor) confesses she was bulimic as a child. Six years before Zoolander, Taylor played Marcia Brady in The Brady Bunch Movie. Maureen McCormick played Marcia in the original Brady Bunch TV series, who actually did suffer from bulimia.