Bedrift O - Blindern
- Observator
- Odea AS
- Osirion AS
- Oivi AS
- Ostomycure AS
- Oleksandr Vynokurov
- Oslo Piratparti
- Olena Korobkina
- Oleksandr Vorobtsov
- Olena Pidhirna
- Olesia Chestneisha
- Oleksandr Khlyzov
- Oksana Zhminko
- Osloensis Finans
- Oxy Solutions AS
- Omniscient Medical AS
- Open Mind AS
- Ocean Visuals AS
- Oslostudentenes Radioklubb
- Oslo Messingkvintett DA
- Oslostudentenes Radioklubb
- Olsholt Invest AS
- Oslo Maritime Stiftelse
- Oslo Maritime Stiftelse
- Overlege Andvords Tuberkuloselegat
- Otto Løvenskiolds Legat
- Oslo Science City
- Omnivision Technologies Norway AS
- Oslo Science City
- Oslo Mental Forensic Group AS
- Otto Helge Hjellegjerde Agenturer AS
- Oslo Wu-Tan Guoshu Klubb
- Oslo Wu-Tan Guoshu Klubb
- Oslo Mental Forensic Group Mipco AS
- Oslo MS-forening - Multippel Skleroseforening
- Overrettssakfører Axel Brynies Helga Brynies og Adelheid Jordans
- Olav Paus Grunts Legat ved Universitetet i Oslo
- Overrettssakfører Axel Brynies Helga Brynies og Adelheid Jordans Legat