"SOS" (working title; "Turn Me On") was written by Benny Andersson, Björn Ulvaeus and Stig Anderson and was recorded at Glen Studio on 22–23 August 1974.

The title itself was coined by Stig, though the lyrics he provided were re-written by Ulvaeus.

"SOS" was among the first of three songs recorded for the group's 1975 album, ABBA.