Science fiction films are films where plot premises generally (1) depend on a scientific development or concept not actualised at the time of filming, or at least not advanced to the degree depicted in the film; or (2) present a vision of the future based on extrapolations of current trends in society. Science fiction film dates back to the earliest days of cinema, and it continues to flourish in the 21st century. While science fiction films valorise science, they just as often distrust it. As a genre, science fiction often raises basic philosophical issues: the meaning of being human, the way in which humans perceive reality, and humanity’s place in the universe, among others.

Science fiction films are generally set in the near or distant future, or an alternate present slightly more advanced than the contemporary moment. At other times, the setting may be an alternate past where scientific equipment or processes are far in advance of the actual technology of the period depicted. Disney’s 20,000 Leagues under the Sea (1954), for example, takes place in the 19th century, but the sophisticated submarine and underwater equipment at its centrepiece are far more advanced than technologies during that time. As such, the film qualifies as science fiction rather than as an adventure film.