Continuity mistake: When Zoolander, Hansel and Matilda are drinking the tea near the end of the movie, the "steam" in Zoolander's cup keeps on changing to from overflowing the cup, to half way down and none. This is without ever refilling his cup. He can even be seen blowing some of the steam out and next thing it's full again.
Factual error: There is one scene towards the end when Matilda is talking to her assistant and two clocks showing the times of Tokyo and Hong Kong are visible on the wall behind. In reality Tokyo is one hour ahead of Hong Kong, but the clock clearly shows Hong Kong as one hour ahead of Tokyo. The Frankfurt clock is also an hour slow, assuming the Chicago clock is the correct one.
Continuity mistake: During the 'Eugoogalizer' conversation between Matilda and Zoolander, look behind Derek, you see two men getting into a car next to the one Zoolander is going to climb into. As Derek is saying "Mugatu, if you knew anything" the men are about to get in but in the next shot they're already in the car.
Continuity mistake: In the scene where Hansel, Matilda and Derek are in the kitchen, the morning after the orgy, everyone else is asleep in the background. Derek's mobile phone rings and then there is a shot of Matilda. Behind her you can see that they are now sat holding phones up to their ears, then when we next see them they are asleep again. This is because the joke where they all answer their phones was cut, leaving only Derek and the chef who answer theirs in the final cut.
Continuity mistake: When David Bowie steps forward to Hansel and Derek, he grabs his hands around their shoulders. As the shot changes from Bowie's face to Hansel's, his hand is gone from Hansel's shoulder, but after the shot turns to Derek and then back to the view of the three of them as it was from the beginning, his hand is back. There's a shot of the back of Hansel's neck with no hand, the angle changes to the front again and the hand is back.