The film's script originally contained a mention of Alexander Dane having been knighted by Queen Elizabeth. Alan Rickman asked that this be changed because he believed it was inconsistent with the character, and all mentions of the knighting were removed; however, the character remains listed as "Sir Alexander Dane" in the credits

When Sigourney Weaver and Tim Allen crawl through the air ducts to stop the ship from exploding, she complaints about going trough air ducts again (Aliens), then complains about crossing over a big fan (Aliens & Alien 3).

At the end of the film, during the 'trailer' for the return of Galaxy Quest the series the voiceover mentions an absence of '18 years'. This is the same length of time between the first two Star Trek series (1969-1987, not counting the films). A nice touch.

The Thermians says that they are from the Klaatu Nebula. Klaatu is the name of the alien who visits Earth in "The Day the Earth Stood Still"(1951). Submitted by Dr Wilson

The scene near the end of the film where the bad guy kills all of the Galaxy Quest crew is very similar to a scene in the '70s British sci-fi TV show Blake's 7. In that scene, the crew are shot one by one in the same fashion as in this scene.

Apparently Sigourney asked and was allowed to keep the devices used to pump up her breasts so much. Some sort of silicon pad thing, I think.

In interesting contrast to Guy's frequent ranting about how he, as the only unnamed character, will be the first to die, in the sequence where Sarris enters the command deck and shoots everyone, Guy is the only crewmember who is NOT shown getting shot.