"Theef" is the fourteenth episode of the seventh season of the science fiction television series The X-Files. It premiered on the Fox network in the United States on March 12, 2000. It was written by Vince Gilligan, John Shiban, and Frank Spotnitz and directed by Kim Manners. The episode is a "Monster-of-the-Week" story, unconnected to the series' wider mythology. "Theef" earned a Nielsen household rating of 7.4, being watched by 11.91 million people in its initial broadcast.