The Portal 2 soundtrack was composed by Mike Morasky, with the exception of the songs “Want You Gone” composed by Jonathan Coulton, “Offering,” composed by Larry Stephens, an arrangement of Little Prelude in C Minor, BWV 934 by Johann Sebastian Bach, and “Exile Vilify,” composed by The National.

While the music can be found in the game files, most tracks are unmixed and can only be fully experienced in-game, as most of the time the testing elements provide additional musical tones. The soundtrack is largely electronic and differs from the quiet ambient music used in the Portal soundtrack in that it is often upbeat.