O'ryan
O-town
O-zone
O.a.r. (of A Revolution)
Oasis
Obie Trice
October Fall
Ok Go
Ol' Dirty Bastard
Oleander
Olivia
Omarion
Omnikrom
One Chance
One True Voice
One Voice
OneRepublic
Opm
Orgy
Orson
Otep
Our Lady Peace
Ours
Outkast
Outlandish
Oxide & Neutrino
Ozma
Ozzy Osbourne
