Bedrift O - Vøyenenga
- O. Reistad AS
- Oslo Glasscoating ANS
- Olav Carlsson
- Oslo Bilutleie AS
- Outlet Invest AS
- Ophelia Frisørene AS
- Oyama Karate Bærum
- Ocz Storage Solutions INC
- Oyama Karate Bærum
- Ordsmeden Thorgeir Holm
- Ole Gunnar Honningsøy
- O. Johanssen Bakery AS
- Oro Posters By Rögnvaldsson
- Optimax - Bedriftsrådgiving Steinar Bang Fylling
- Oslo Bærum Vann & Varme AS