Stargate Atlantis, often abbreviated as SGA, is a Canadian-American military science fiction television series and part of MGM's Stargate franchise. The show was created by Brad Wright and Robert C. Cooper, as a spin-off series of Stargate SG-1 created by Wright and Jonathan Glassner after the release of Stargate (1994). The first three seasons of the television series were broadcast by Sci Fi Channel and The Movie Network before the series moved only to Sci Fi Channel for its last two seasons, meaning a release of 100 episodes before the series was cancelled. Stargate Atlantis premiered on Sci Fi Channel on July 16, 2004; its final episode premiered on Sci Fi Channel on January 9, 2009. The television series was filmed in and around Vancouver, Canada.

The story of Stargate Atlantis follows the cliffhanger episode on Stargate SG-1's seventh season finale "Lost City", where SG-1 found an outpost made by the race known as the Ancients in Antarctica. After the events of Stargate SG-1 season eight premiere "New Order", the Stargate Command sends an international team to investigate the outpost. Soon, Dr. Daniel Jackson discovers the location of the greatest city created by the Ancients, Atlantis. The story unfolds when the members of the expedition encounter the Wraith, the race that defeated the Ancients ten thousand years ago.