- Occupational safety and health
- Orthopedic shoe store
- Organic restaurant
- Observatory
- Office equipment rental service
- Office refurbishment service
- Optical products manufacturer
- Oyster supplier
- Outlet store
- Office equipment repair service
- Oral surgeon
- Otolaryngology clinic
- Outdoor activity organiser
- Orthodontist
- Oil store
- Orphanage
- Organic farm
- Orchid farm
- Olive oil manufacturer
- Outdoor bath