- Opium Warlords
- OK Cobra
- On
- Orchard
- Optimum Wound Profile
- Otmaro Ruíz
- Oskar Schoenning
- Otis Grand
- Oscar Toney, Jr.
- Opaque Lucidity
- Osiris
- Onna
- Olavi Uusivirta
- Omicron
- Original Concept
- Oddjobs
- Organized Noize
- Offertorium
- One Way Letter
- Or, The Whale
- Oskar Aichinger
- Orquesta Cubana De Musica Moderna
- Odin's Court
- Offwhyte
- Ornette Coleman & Prime Time
- Orquesta Guayacan
- Old Dead Tree
- Orup
- Oro Norteño
- Odious Sanction
- Omillio Sparks
- Orange Humble Band
- OK OK
- Orion the Hunter
- Octurn
- One Hit Wonder
- Oranj Symphonette
- Olga Manzano y Manuel Picón
- Omar Garcia
- Old & In the Gray
- Ozzie Ahlers
- Original Silence
- Ohio
- Omasphere
- Offcutts
- Only Living Witness
- O! The Joy
- Octobop
- Opposite Exhale
- Osvaldo Chacón
- Ossatura
- Old Bear
- October Game
- Office
- Omar Pedrini
- Our Crooked Teeth
- Outsmarting Simon
- Orwell
- Open Road
- Otis Blackwell
- Oleg Serkov
- O Pioneers!!!
- Optimystical
- Otto Lechner
- Other Dimensions in Music
- Once Nothing
- Ov
- Oprah Winfrey
- Oliver Hart
- Oh-OK
- One Soul Thrust
- Open Loose
- Oscar G
- Over My Dead Body
- One by One
- One In A Million
- Oliver Neveux
- Odwalla
- Out of Order
- Oscar Levant
- Overwhelming Colorfast
- Orchestra U.S.A.
- Owen Temple
- Osoka
- Ollie Halsall
- Omendark
- Oscar Perry
- Oriental Brothers
- Ocho
- One Second 2 Late
