- Oral & Maxillofacial Surgery
- Oral & Maxillofacial Surgery Associates
- Oral Surgery Associates
- Orange Coast Title
- Orange Julius
- Orange Leaf
- Orbit-tech
- Orchard
- Orchard Apartments
- Orchard Inn
- Orchard Park Apartments
- Orchard Supply Hardware
- Orchard Supply Hardware - Commercial Services
- Orchid Cleaners
- ORCO Construction Supply
- Oreck Factory Showroom
- Oreck Floor Care Center
- Oreck Floor Care Centers
- Oregon Child Development Coalition
- Oregon Realty
- O'Reilly Auto Parts
- Organized Living
- Orica USA
- Orient Express
- Oriental Buffet
- Oriental Decor
- Oriental Food Market
- Oriental Garden
- Oriental House
- Oriental Kitchen
- Oriental Market
- Oriental Nails
- Oriental Palace
- Oriental Restaurant
- Oriental Rug Gallery
- Oriental Treasures
- Original Cookie CO
- Original Cookie Company
- Original Italian Pizza