Stargate SG-1 (often abbreviated as SG-1) is an American-Canadian military science fiction television series and part of Metro-Goldwyn-Meyer's Stargate franchise. The show, created by Brad Wright and Jonathan Glassner, is based on the 1994 feature film Stargate by Dean Devlin and Roland Emmerich. The television series was filmed in and around the city of Vancouver, British Columbia. Showtime broadcast the first five seasons beginning in 1997 before the series moved to the Sci Fi Channel for its last five seasons. The final episode premiered on Sky1 in the United Kingdom on March 13, 2007, three months before its United States premiere. With 10 seasons and 214 episodes Stargate SG-1 surpassed The X-Files in 2007 as the longest-running North American science fiction series on television.

The story of Stargate SG-1 begins one year after the events of the feature film. A network of ancient alien devices called Stargates connects the far reaches of several galaxies for near-instantaneous interstellar travel. Stargate SG-1 chronicles the adventures of SG-1, the flagship team of over two dozen teams from Earth who explore the galaxy and defend Earth against alien threats such as the Goa'uld, Replicators and later the Ori. The composition of the SG-1 team is stable in the show's first five seasons but changes several times in the remaining seasons. The series expands upon many Ancient Earth mythologies such as Egyptian mythology, Norse mythology, and Arthurian legend. The 2008 direct-to-DVD films Stargate: The Ark of Truth and Stargate: Continuum continue the adventures of SG-1; the third direct-to-DVD film, titled Stargate: Revolution, was confirmed in April 2009.