Star Trek is an American science fiction entertainment series and media franchise. The Star Trek fictional universe created by Gene Roddenberry is the setting of six television series including the original 1966 Star Trek, in addition to ten feature films (with an eleventh in production), dozens of computer and video games, hundreds of novels and other fan stories, as well as a themed attraction in Las Vegas. The original TV series alone is one of the biggest cult phenomena of modern times.

In the Star Trek universe, humanity developed faster-than-light space travel, using a form of propulsion referred to as "warp drive", following nuclear war and a post-apocalyptic period in the mid-21st century. According to the story time line, this happened on April 4th, 2063. Later, humans united with other sentient species of the galaxy to form the United Federation of Planets. As a result of the intervention and scientific teachings of the Vulcans, an advanced alien race, humanity largely overcame many Earth-bound frailties and vices by the twenty-third century. Star Trek stories usually depict the adventures of human and alien beings who serve in the Federation's Starfleet.

The protagonists are essentially altruists whose ideals are sometimes only imperfectly applied to the dilemmas presented in the series. The conflicts and political dimensions of Star Trek form allegories for contemporary cultural realities; Star Trek: The Original Series addressed issues of the 1960s, just as later spin-offs have reflected issues of their respective eras. Issues depicted in the various series include war and peace, authoritarianism, imperialism, class warfare, economics, racism, human rights, sexism and feminism, and the role of technology. Gene Roddenberry has stated that by creating "a new world with new rules, I could make statements about sex, religion, Vietnam, politics and intercontinental missiles. Indeed, we did make them on Star Trek: we were sending messages and fortunately they all got by the network"