Once upon a time, Galaxy Quest was an incredibly popular science fiction television show. Then it got cancelled but unlike most shows, it attained cult status and now, eighteen years later, the cast of actors find themselves unable to escape it. Forever typecasted by their performances and unable to find other work, they make a meager living opening electronic stores and appearing at Galaxy Quest Conventions. Until their biggest fans show up.
A highly advanced alien species known as the Thermians (with no concept of fiction) have seen the old broadcasts of Galaxy Quest and have assumed their shows are 'historical documents' and modeled their entire society based on the peaceful ethos and high-minded principles of the Questers. But the pacifistic Therians find themselves overwhelmed in a war against a race of tyrannical alien overlords led by Sarris. Desperate for help, they have come to Earth fully expecting their legendary 'heroes' to save them.
- Tim Allen as Jason Nesmith
- Sigourney Weaver as Gwen DeMarco
- Alan Rickman as Alexander Dane
- Tony Shalhoub as Fred Kwan
- Sam Rockwell as Guy Fleegman
- Daryl Mitchell as Tommy Webber
- Enrico Colantoni as Mathesar
- Robin Sachs as Gen. Roth'h'ar Sarris
- Justin Long as Brandon
- Missi Pyle as Laliari
- Patrick Breen as Quellek
- Sam Lloyd as Neru
- Rainn Wilson as Lahnk