Bedrift O - Skedsmokorset
- Olinco AS
- Oleka AS
- Orkestra AS
- Onemed AS
- Osn AS
- Onninen AS
- Orlund Consulting
- Oslo Bowlingskole
- Odinvangen Huseierforening
- Olsen Steinar
- Oddveig Gundersen
- Osprey Event AS
- Odinvangen Huseierforening
- Oddis Holding AS
- Office Garden AS
- Outlet Scandinavia AS
- Osprey Event AS
- Obv Drift AS
- Oslo Vedhandel AS
- Okbay Beyene
- Olivia Hansson
- Ola Wærhaug
- Oslo Fotograflaug
- Optikk 2020 AS
- Obrovac Linda
- Ovidijus Bladzinauskis
- Olav Amundsen
- Ower Trafikkskole
- Ola Wærhaug
- Oslo Kranbilservice AS
- Office Riga
- Os Montasje AS
- Otto Olsen AS
- OneMed Services AS
- Optimus Byggutvikling AS
- Oslo Christian Assembly
- Osteopat Jansen Hasle
- Oslo Auto Express AS
- Oslo Christian Assembly
- Oslo Bilhjelp Holding AS
- Oppover Bjørn Skovli
- Ordo Aqua Vitae
- Origo-DA Sigmund Danielsen
- Otto Olsen AS Avd Produksjon
- Oiltalk Vegard Hasselberg
- Oskars Bartkevics Montasje
- Opp Av Sjøen AS
- Ojr Rydland Holding AS
- Otto Olsen Invest AS
- On Beach Invest AS
- Oslo Blaaseorkester SA
- Otto Olsen Holding AS
- O.B.Wiik AS
- Omnfoto Ole Martin Nilsen
- Oslo og Omegn Modellhelikopterklubb
- On Our Own Productions AS
- Oslo Bud & Vare AS
- Organisasjon for Narvik-Tamiler
- Oslo Kjøl & Klima AS
- Oldtimer Service Bjarne Koren
- O.B.Wiik Covers AS
- O.B.Wiik International AS
- O.B.Wiik Services AS
- Open Top Sightseeing Norway AS
- O.B.Wiik Hall AS
- O.B. Wiik A/S Avd Salg
- O.B.Wiik Utleie AS
- O.B. Wiik A/S Avd Utleie
- Oslo Drift og Vedlikehold AS
- Oslo og Akershus Takst Strøm
- Olsens Hus og Hytte Service
- Oslo Bilhjelp Hans-Erik Gaarder
- Opplæringskontoret for Service og Samferdsel SA