- Oaagaada
- Objets Trouvés
- Obliquartet
- Odd-Arne Jacobsen
- Odean Pope
- Odyssey Bogusevich
- Odyssey The Band
- Oil My Member
- Okay Temiz
- Okkyung Lee
- Okuden Quartet
- OL
- Olavi Louhivuori
- Old and New Dreams
- Ole Amund Gjersvik
- Olga Konkova Trio
- Olgierd Kaplecki
- Oliver Lake
- Oliver Lake Big band
- Oliver Lake Organ Trio
- Oliver Lake Quartet
- Oliver Lake Quintet
- Oliver Lieb
- Olivier Aude
- Olivier Hutman
- Olo Walicki
- Olof Johansson's the Jazzy Project
- Oluyemi Thomas
- OM
- Omar Vázquez K
- Omri Ziegele
- On Ka'a Davis
- One Two Free Fall
- Oneirogen
- Open Sky
- Open String Department
- Orang'e
- Orange
- Orange Then Blue
- Orchestre National de Jazz
- Oregon
- Oren Ambarchi
- Ori Dakari
- Original Mind
- Ori Dakari
- Original Mind
- ORIGINAL PHALANX
- Ornette Coleman
- Ornette Coleman & Prime Time
- Ornette Coleman Quartet
- Ornette Coleman Quintet
- Ornithopter
- Orter Eparg
- Oscaryvan Garzón Trío
- Oskar Aichinger
- Other Dimensions In Music
- Otis Sandsjö
- Otomo Yoshihide
- Otomo Yoshihide's New Jazz Ensemble
- Otomo Yoshihide's New Jazz Quintet
- Ottone Pesante
- Ove Ingemarsson
- Owen Allen
- Owl Xounds Exploding Galaxy
- Oxbow