The fourth season of Stargate Atlantis, an American-Canadian television series, began airing on September 28, 2007 on the US-American Sci Fi Channel.

Other season four regular cast members include Joe Flanigan, Rachel Luttrell, Jason Momoa and David Hewlett.

With the season premier, "Adrift", Amanda Tapping replaces Torri Higginson in the opening credits sequence, with Paul McGillion no longer appearing.

Christopher Judge has a cameo appearance as his Stargate SG-1 character Teal'c in "Reunion" and guest stars in the episode "Midway".

Shortly after, fans who used iTunes to download "Adrift" discovered that they had in fact purchased "Doppelganger" instead, three weeks before it was set to premiere on Sci Fi Channel in the USA.