- Oriental goods store
- Orchestra
- Office
- Okonomiyaki restaurant
- Occupational medical physician
- Offal barbecue restaurant
- Oilfield
- Office services
- Olive oil manufacturer
- Opera company
- Outdoor bath
- Oral surgeon
- Office of Vital Records
- Open air museum
- Open university
- Office supply wholesaler
- Off roading area
- Office accessories wholesaler
- Oncologist
- Office supply