- Oppo
- Optex
- Optimus
- Optoma
- ORANGE
- ORAY
- Oregon
- Oregon Scientific
- Orion
- Oster
- OTAX
- Otio
- OvisLink
- OXANCE
- Oxygen
- Ozone
- Packard Bell
- PALISADE
- Palm
- Panasonic
- Pantech
- PARADOX
- Paragon Software
- Parallels
- Parkside
- ParkZone
- Parrot
- Partner
- PEAQ
- Peavey
- Pelgrim
- Pentair
- Pentax
- Pentax Série
- PERFORMANCE
- Peugeot
- Pfaff
- PGP
- Philco
- Philips