The X-Files is an American science fiction drama television series, which is a part of The X-Files franchise, created by Chris Carter. The program originally aired from September 10, 1993 to May 19, 2002, spanning nine seasons and 202 episodes. The show was a hit for the Fox network, and its characters and slogans, such as "The Truth Is Out There", "Trust No One", and "I Want to Believe" became popular culture touchstones in the 1990s. Seen as a defining series of its era, The X-Files tapped into public mistrust of governments and large institutions, and embraced conspiracy theories and spirituality as it centered on efforts to uncover the existence of extraterrestrial life. The series spawned a spin-off show, The Lone Gunmen.

In the series, FBI special agents Fox Mulder (David Duchovny) and Dana Scully (Gillian Anderson) are the investigators of X-Files: marginalized, unsolved cases involving paranormal phenomena. Mulder is a believer in the existence of aliens and the paranormal while Scully, a skeptic, is assigned to make scientific analyses of Mulder's discoveries which could ultimately be used to debunk Mulder's work and thus return him to FBI mainstream.[1] Early in the series both agents become pawns in a larger conflict, and come to trust only each other. They develop a close relationship, which begins as a platonic friendship, but develops into a romantic relationship by the end of the series' run.

In addition to the series-spanning story arc, "monster of the week" episodes made up roughly two-thirds of the series. In such stand-alone episodes, Mulder and Scully investigated strange crimes which often had no long-term effect on the storyline, though the episodes contributed to the show's background. A 1998 feature film, The X-Files, has been released. This was followed in 2008 by a post-series film, The X-Files: I Want to Believe.

In the last two seasons, Gillian Anderson became the star as David Duchovny appeared intermittently, and new central characters were introduced: FBI agents John Doggett (Robert Patrick) and Monica Reyes (Annabeth Gish). Mulder and Scully's boss, Assistant Director Walter Skinner (Mitch Pileggi), also became a central character. By the time the series ended, The X-Files had become the longest-running science fiction series in U.S. television history, though it was subsequently surpassed by Stargate SG-1 in 2007 and by Smallville in 2011. The series won the Golden Globe Award for Best Television Series ΓÇô Drama three times (1994, 1996, and 1997), and Duchovny and Anderson received multiple award nominations for their performances.