- Oiler -- O.J. Ekemonde
- Oj Hernandez -- Ojo De Vidrio
- Ojo Rojo -- OK Go
- OK Hemingway -- Okai
- Okaidja -- Okay Paddy
- Okay Samurai -- Okie Dokie
- Okie Rosette -- Oklahoma Tornadoes
- Oklahomo Trio -- Ok.Suitcase
- Oksygen -- 奥華子
- Oku Hanako -- Ol' Jack
- Ol' Kainry -- Ola Kielb
- Ola Kvernberg -- Olaf Bär
- Olaf Bär [Baritone] -- Olaf Stötzler
- Olaf Thörsen -- Olatz Zugasti
- Olaus -- Olav Werner
- Olav Werner -- Old Baptist Church
- Old Basford -- Old Fashioned Revival Hour Choir