- Oxygen equipment supplier
- Outdoor furniture store
- Office accessories wholesaler
- Oil refinery
- Oil wholesaler
- Occupational safety and health
- Oil depot
- Outdoor swimming pool
- Office equipment repair service
- Orthopedic shoe store
- Orthopedic clinic
- Orthopedic surgeon
- Occupational health service
- Ophthalmologist
- Osteopath
- Oral and maxillofacial surgeon
- Opera house
- Outdoor clothing and equipment shop
- Oldsmobile dealer
- Open air museum