"Fortress" is a song by American garage rock band Thee Oh Sees, released as a limited edition single on February 12, 2016 on Castle Face Records.

The song, and its b-side, "Man in a Suitcase", were recorded during the same sessions as the band's sixteenth studio album, Mutilator Defeated At Last (2015).

In a positive review for Pitchfork, Evan Minsker praised the contributions of drummer Nick Murray and the consistency of Thee Oh Sees' output: "Fortress" isn't an adrenaline rush on the level of "Tunnel Time".

It's muscular, sure, but it's also patient—another sign they could keep churning out solid material for years to come.

"[1] In another positive review, Stereogum's Tom Breihan wrote: "It's a jagged, percussive banger driven by a slashing guitar riff and a storm of drums, and it's very much the sort of thing that will hit like a bomb when they play it live.