- Optical products manufacturer
- Office supply
- Oncologist
- Osteopath
- Oilfield
- Orchestra
- Outboard motor store
- Oral and maxillofacial surgeon
- Outdoor bath
- Open university
- Organ donation and tissue bank
- Off track betting shop
- Office supply wholesaler
- Opera company
- Oil field equipment supplier
- Oxygen cocktail spot
- Office equipment rental service
- Oriental medical clinic
- Oxygen equipment supplier
- Oriental medicine store