- Office supply store
- Outdoor furniture store
- Others
- Outerwear store
- Orthodontist
- Orthotics & prosthetics service
- Occupational health service
- Oil change service
- Outlet mall
- Oil field equipment supplier
- Oilfield
- Outdoor sports store
- Oil refinery
- Optometrist
- Optician
- Osteopath
- Occupational safety and health
- Oil & natural gas company
- Occupational medical physician
- Occupational therapist