Bedrift O - Fjerdingby
- Othman
- Olsgård
- Oskanor AS
- Opsaltunet AS
- Oliviafoto AS
- Olafsson Sikkerhet
- Oliverot Bil
- Ovidijus Judikavicius
- Olha Krezub
- Olivier Chateau
- Orooj Mahmood AS
- Orfjell Holding AS
- Oslo-Nordstrand Soroptimistklubb
- Open Payments Europe AS
- Opulent Property Holding AS
- Opulent Property Investors AS
- Orfjell Consulting Solutions
- Odd H Jensen AS
- Ole-Petter Hamnvik Endokrinologi
- Olsen Kosthold og Trening
- Oslo Bad & Snekkeri AS
- Opulent Property Investors II AS
- Oslo Bygg og Bad AS
- O-B Bygg Kenneth Olsen-Bjerke