"Improbable" is the thirteenth episode of the ninth season and the 195th episode overall of the science fiction television series The X-Files. The episode first aired in the United States and Canada on April 7, 2002, on Fox, and subsequently aired in the United Kingdom. It was written and directed by series creator and executive producer Chris Carter. The episode is a "monster-of-the-week" episode, a stand-alone plot which is unconnected to the mythology, or overarching fictional history, of The X-Files. The episode earned a Nielsen rating of 5.1 and was viewed by 9.1 million viewers. The episode received mostly positive reviews from critics.

The ninth season of the American science fiction television series The X-Files commenced airing in the United States on November 11, 2001, concluded on May 19, 2002, and consists of twenty episodes. The season takes place after Fox Mulder goes into hiding, following the events of the eighth season finale, "Existence". As such, the main story arc for the season follows Dana Scully, John Doggett, and Monica Reyes on their hunt to reveal a government conspiracy involving the elaborate and malevolent creation of "Super Soldiers".