"Three of a Kind" is the twentieth episode of the sixth season of the science fiction television series The X-Files. It premiered on the Fox network on May 2, 1999 in the United States. The episode was written by Vince Gilligan and John Shiban, and directed by Bryan Spicer. The episode is a "Monster-of-the-Week" story, unconnected to the series' wider mythology. "Three of a Kind" earned a Nielsen household rating of 8.2, being watched by 12.9 million people in its initial broadcast. The episode received mixed to positive reviews from critics, with some noting that the episode served as a stop-gap.