The Lone Gunmen is an American conspiracy fiction thriller drama television series created by Chris Carter, Vince Gilligan, John Shiban, and Frank Spotnitz. The program originally aired from March 4, 2001 (2001-03-04), to June 1, 2001 (2001-06-01), on Fox. It is a spin-off of Carter's science fiction television series The X-Files and as such is part of The X-Files franchise, starring several of the show's characters. Despite positive reviews, its ratings dropped, and the show was canceled after thirteen episodes. The last episode ended on a cliffhanger which was partially resolved in a ninth season episode of The X-Files entitled "Jump the Shark".

The series revolves around the titular trio The Lone Gunmen: Melvin Frohike, John Fitzgerald Byers, and Richard Langly, private investigators who run a conspiracy theory magazine. They had often helped FBI Special Agent Fox Mulder on The X-Files.