- Original Italian Pizza & Restaurant
- Original Pizza
- Original Roadhouse Grill
- Origins
- Origins Natural Resources
- Oritani Savings Bank
- ORIX Financial Services
- Orkin
- Orkin Exterminating Co
- Orkin Pest Control
- Oroweat Baking Company
- Orscheln
- Orthodontic Associates
- Orthodontic Care Specialists
- Orthodontic Centers of America
- Orthodontic Specialists
- Orthodontics
- Orthopaedic & Sports Medicine Center
- Orthopaedic Center
- Orthopedic Associates
- Orthopedic Rehabilitation
- Orthopedic Specialists
- Orthopedic Sport Physical Therapy
- Orthopedic Surgeons
- Orthorehab
- Orvis
- Osaka
- Osaka Japanese Restaurant
- Oscar's
- Osco Drug - Pharmacy General MDSE
- Osco Drug - Regular Hour Pharmacies- Indianapolis- Pharmacy General
- Osco Drug - Regular Hour Pharmacies- Kansas City MO
- Oshkosh B'Gosh
- Oshkosh B'Gosh Factory Store
- Oshman's Sporting Goods
- Osram Sylvania
- Osteoporosis Center
- Osterman Jewelers
- Other Mother's