The X-Files (also known as The X-Files: Fight the Future) is a 1998 American science fiction-thriller film written by Chris Carter and Frank Spotnitz, and directed by Rob Bowman. It is the first feature film based on The X-Files series created by Carter that revolves around a fictional FBI paranormal investigation unit called the X-Files. Four main characters from the television series appear in the film: David Duchovny, Gillian Anderson, Mitch Pileggi and William B. Davis reprise their respective roles as FBI agents Fox Mulder and Dana Scully, FBI Assistant Director Walter Skinner and the Cigarette-Smoking Man. The film's tagline and sub-title is Fight the Future.

The story follows agents Mulder (Duchovny) and Scully (Anderson), removed from their usual jobs on the X-Files, and investigating the bombing of a building and the destruction of criminal evidence. They uncover what appears to be a government conspiracy attempting to hide the truth about an alien colonization of Earth. In addition to dealing with mysterious adversaries and unhelpful bosses, the agents face the end of their professional partnership. When Scully is abducted, Mulder goes to Antarctica to rescue her and finds a huge underground laboratory in an alien space craft containing cocooned aliens. The lab is destroyed and he witnesses the alien spacecraft flying off into the distance. At the end of the film, the X-Files unit is reopened. Viewed in the context of The X-Files chronology, the film's story takes place between seasons five (episode The End) and six (episode The Beginning) of the television series, and is based upon the series' extraterrestrial mythology.

Chris Carter decided to make a feature film to explore the show's mythology on a wider scale, as well as appealing to non-fans. He wrote the script with Frank Spotnitz at the end of 1996 and, with a budget from Fox, filming began in 1997, following the end of the show's fourth season. Carter assembled cast and crew from the show, as well as some other, well-known actors such as Blythe Danner and Martin Landau, to begin production on what they termed "Project Blackwood". Mark Snow continued his role as X-Files composer to create the film's score.

The film premiered on June 19, 1998 in the United States, and received mixed reviews from critics. Although some enjoyed the style and effects of the film, others found the plot confusing and viewed it as little more than an extended episode of the series. A sequel, The X-Files: I Want to Believe, was released ten years later.