- Oldsmobile dealer
- Optical wholesaler
- Optical products manufacturer
- Office
- Oil change service
- Orthodontist
- Orchestra
- Office equipment supplier
- Off track betting shop
- Oral and maxillofacial surgeon
- Oil field equipment supplier
- Outdoor clothing and equipment shop
- Outlet mall
- Oral surgeon
- Orchard
- Orthodox church
- Outdoor activity organiser
- Otolaryngology clinic
- Olive oil manufacturer
- Observatory