Bedrift O - Bekkelaget
- Optimert AS
- Olefondet AS
- Oxmeis AS
- Osp AS
- Orakel AS
- Oka AS
- Overbird AS
- Ocius AS
- Onsirat AS
- Omrani Music
- Oslo Malerbedrift AS
- Offside Ungdomsbedrift
- Oslo Sveisemek
- Oscar Jøraandstad
- Opplæring Nitschkes
- Ohoh Holding AS
- Olav Investerer AS
- Onemanarmy Skjølberg
- Ogo Invest AS
- Olav Jetlund AS
- Odd Hesselberg
- Olav Haddeland
- Orset Sport
- Objektiv Partner AS
- Oksdøl Invest AS
- Office Care AS
- Ola Heining
- Othmans Import
- Obabo Holding AS
- Ok Maritime AS
- Ovesen Musikk
- Oberst Invest AS
- Osloidrettens Studieforbund
- Ormøy Menighet
- Oslo Bedriftsidrettskrets
- Oslo Bandykrets
- Odajakob Invest AS
- Onmii Trading AS
- Oslo Kfum
- Oslo Kiteskole
- Oslo Terrengsykkelcup
- Opat Holding AS
- Oslo Mood AS
- Osloidrettens Studieforbund
- Oslo Skikrets
- Oslo Friidrettskrets
- Ordo Investeringsselskap AS
- Oslo Idrettskrets
- Oslo Fotballkrets
- Oobro Fossen
- Oslo Skytterkrets
- Ohb Trading AS
- Offshore Piping AS
- Olav Vhile
- Oko Taxi
- Oug Holding AS
- Oslo Container Terminal AS
- Ocean King AS Konkursbo
- Ocean King AS Konkursbo
- Ohm El.installasjon AS
- Odd Hesselberg Design
- Odd Henning Arntzen
- Oslo Byggeadministrasjon Invest AS
- Olaf Ek Jacobsen
- Oslo Hage Graveservice AS
- Oslo Prop House AS
- Oslo Idrettshaller AS Tvangsavviklingsbo
- Oslo Idrettshaller AS Tvangsavviklingsbo
- Ole Marius Christiansen AS
- Oslo Perl Mongers
- Oss på Hjørnet AS
- Oppussingtjenester Marcin Kubas
- Oslo Svømmekrets Kretskontor
- Ole Ragnar Walsig
- Oda Egjar Starheim
- Oslo Malermesterlaugs Dameforening
- Oddane Marius Maslahat
- Oscar Valland Lund
- Odd Arvid Strømstad
- Olav Torstein Dolve
- Otto Bock Scandinavia
- Oslo Cheer Klubb Galaxy
- Oslo Cheer Klubb Galaxy
- Oddfrid Ropstad Costume Design
- Orbis Investment Advisory Limited
- Olsen Facit Consult Elisabeth
- Osa Ie Anleggsavdelingen Majorstua
- Osiris Robert Marc Friedman
- Olaf A B Styrmoe Enk
- Oslo Vintage Mari Kjendsli
- Oslo og Akershus Basketballkrets
- Oslo og Akershus Rytterkrets
- Oslo Fremskrittsparti Bydelslag Nordstrand
- Olaf A B Styrmoe Holding AS
- OBS-Vær Varsom Per Helbostad
- Oleg Football Development Coaching Olegs
- Oacm Ocean Alliance Conservation Member
- Olaf Billes Legat for Blomsterhagens Utvikling
- Oaek - Oslo Akershus Elektro og Klima AS
- Otto Bock Scandinavia Norsk Avdeling Av