- Oasis
- Oberheim
- Ocean Way
- OCProducts
- Odeseimusic
- Odyson
- Odyssey
- OEM
- Oemgenuine
- OFFICECOLOR
- OffSet
- Ohm Force
- Ohma World
- Oladance
- Old Blood Noise Endeavors
- Olivieri
- OMK
- One Control
- ONLYU
- OnStage Stands
- Optima
- Orange Amplifiers
- Orange County Drum & Percussion
- Orangewood
- Ordtop
- ORICO
- Ortega
- Ortofon
- ORWETO
- Oscar Schmidt
- OTHER
- Otto Link
- Otto Musica
- OUTLAW DRUMS
- Outlaw Effects
- Output
- OUVISLITE
- Ovation
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- OWC
- Oyaide
- Oydisen
- Oyen Digital