Obie Trice
Obscure Disorder
O.C.
OD
Oddjobs
Odd Nasdam
Offwhyte
Of Mexican Descent
Oh No
Ol' Dirty Bastard
Old World Disorder
Omid
Omniscence
Onecut
Oneway
On U Sound
Onyx
the Opus
Organic Grooves
Organized Konfusion
Originoo Gunn Clappaz
Orko The Sykotik Alien
Outsidaz
Ozomatli