The film is set in a hypothetical world where an entire town is dedicated to a continually running television soap opera, where all but one of the participants are actors. Only the central character, Truman Burbank, is unaware that he lives in a constructed reality, for the entertainment of those outside. The film follows his discovery of his situation and his attempts to escape.
The Truman Show can be considered a parody of the soap opera genre and reality television. It also draws heavily on themes of gnosticism: this religious school teaches that the world we live in is essentially false, and the creation of an somewhat evil and twisted god called the Demiurge. Another religious theme that the film alludes to is the Book of Job of the Old Testament, where the hero is put through a series of trials by God.
There are also strong criticisms of contemporary society; in the film there are people who would do anything for fame and money; the main "characters" in the "show" pretend friendship to Truman, and even Truman's wife is, unknown to him, just an actress.