- Otolaryngologist
- Open university
- Office space rental agency
- Olive oil manufacturer
- Obstetrician-gynecologist
- Ophthalmology clinic
- Outlet mall
- Organic shop
- Oil store
- Office equipment repair service
- Office of a fair trade organization
- Office services
- Outdoor clothing and equipment shop
- Outerwear store
- Orchestra
- Orthopedic shoe store
- Orthoptist
- Oral surgeon
- Orthotics & prosthetics service
- Outdoor swimming pool