The second season of the American cable television series Legion is based on the Marvel Comics character David Haller / Legion, a mutant diagnosed with schizophrenia at a young age. The season is connected to the X-Men film series, and is produced by FX Productions in association with Marvel Television. Noah Hawley serves as showrunner.

Dan Stevens stars as Haller, with Rachel Keller, Aubrey Plaza, Bill Irwin, Jeremie Harris, Amber Midthunder and Jean Smart also returning from the first season to star. They are joined by Jemaine Clement and Hamish Linklater, promoted from guest roles in the first season, and Navid Negahban. A second season of Legion was ordered by FX in March 2017, with filming for the season relocating from Vancouver to California, to take advantage of tax incentives. Production began in September 2017, with practical effects again a priority for the series' crew. The season features the parasitic villain Amahl Farouk / Shadow King, portrayed by Negahban, searching for his original body after being forced out of Haller's mind at the end of the first season.