- Off White Lies -- Office Ladies
- Office of Future Plans -- Official Hot Mess
- Official Karma -- Officium Triste
- Offiong Bassey -- O.F.I.
- Oficina de Cordas -- Ofrenda Para El Cielo
- Ofri Eliaz -- O.G. Dave
- OG Dutch Master -- OG San
- O.G. Sanch -- O.G.C.
- OGC -- OGM Music
- Ogün Sanlısoy -- Oh Astro
- Oh Astro -- Oh, Juliet!
- Oh! Kelly -- Oh! Penelope
- Oh! Penelope -- Oh What A Nightmare
- Oh Whitney -- O´Heller Project
- Ohemaa Mercy -- Ohio State University Marching Band
- Ohio State University Wind Symphony -- oHMEGARED
- Ohmna -- Ohrenbär
- Ohrenfeindt -- Oibek
- Oicho -- Oil & Water