Bedrift O - Homansbyen
- Organisasjonsservice AS
- Orgservice AS
- Onkel AS
- Odeon AS
- Olbios AS
- Oktra AS
- Odb AS
- Ogen AS
- Olsen
- Okkult AS -
- Omnia AS
- Oak
- Olicem
- Olicem
- Outsourcia AS
- Oticon AS
- Oslo Symfoniorkester
- Oslomet Il
- Oslomet Lacrosse
- Onkel Estrup
- Oslomet Gaming
- Oslo Hudlegeklinikk AS
- Orv 38 AS
- Odin Bidco AS
- Orgservice Regnskap AS
- ODEON Kino
- OsloMet - Storbyuniversitetet
- Oda Landewall
- Ombye Consulting
- Oryx Invest AS
- Oppegårdveien Holding AS
- Omundsen Terje
- Ofo Invest AS
- Oslo Barneklinikk AS
- Ofo Holding AS
- Orlando Invest AS
- Oslo Boligutvikling AS
- Oppegårdveien 2 AS
- Oda Landewall AS
- Ofo Services AS
- Oak Tree AS
- Oslo Grammofon DA
- Oslo Skredderstue
- Olena Khodakivska
- Okkult Coco AS
- O19g Q AS
- Olio Holding AS
- Olio Mipco AS
- Odd 8 AS
- Odd Coctailbar AS
- Okkult Holding AS
- Odd Cocktailbar
- Oslo Arkitektforening
- Opera Forlag
- Oslo Ventures AS
- Ourway Tours AB
- Ovesen Film
- Oslo Hudklinikk
- Oslo klinikken
- Oslo Laserklinikk AS
- Olesandr Volynskyi
- Opm-Op AS
- Odd Lunde AS
- Omar Savan
- Omhu Hiba
- Oslo Hudlegekontor AS
- Olaussengården Tomt AS
- Oris Dental AS
- Odin Customs AS
- Oslo Dermatology AS
- O2 Eiendom AS
- Oslo Dermatology AS
- Ove Brevik AS
- Ottosen Basis AS
- Olivia Hegdehaugsveien
- Omhu Bemanning AS
- Omhu Bemanning AS
- Oslo Eiendomssenter AS
- Opplysningsrådet for Veitrafikken
- Oculus Capital AS Konkursbo
- Oculus Capital AS Konkursbo
- Opplysningsrådet for Veitrafikken AS
- Ow Utsira nord AS
- Oslo Light Industries AS
- Onelog Regnbueveien 9 AS
- Oslo Hudlegesenter AS Fq
- Ole Kristian Kleivenes
- Oscars gate 54
- Ola Harder Fredriksen
- Oej 370 Holding AS
- Oslo Science Hub AS
- Oscars gate 35 AS
- Oslo Family Office AS
- Offentlig Bygg Furuset AS
- Oscar Lokalmedisinske Senter
- Othelie S. Brødholt
- Oily By Cherdsri
- Ougendalv Charlotte Ougendal
- Oj Wiig Media
- Oslo Storbymenighet Frikirken
- Objective Maziar Ghahramani
- Oslo Nummer Pinpin
- Oslo City Olio -
- Oslo Community Theatre
- Oslo Community Theatre
- Oslo 3D Laserskanning AS
- Oslo International Angels
- Oslo International Club
- Oslo vest Apartment AS
- Oline Bjerke-Grimnes
- Oslo Korean School
- Oscars gate 30 AS
- Oslo Odontologisk Søvnklinikk AS
- Oslo Helse Legevakt
- Oslo International Hub AS
- Odin Diving Norge AS
- Oris Dental Homansbyen
- Oscar Jacobson Hegdehaugsveien
- Olga-Regnbue Olha Matushevska
- Ole Petter Haugen Consulting
- Onelog Norway Vestby Holding AS
- Onelog Norway Torvstikkeren 10 AS
- Oslo Private Gymnasium - Opg
- Onnec Sweden Norway Filial
- Oslomet - Storbyuniversitetet Studiested Pilestredet
- Onnec Sweden Norway Filial
- Oscars gate 35 Holding AS
- Oscars gate 53-55 AS
- Orange Spa Wiparut Nilapaka
- Ocb Ole Christian Bøe
- Ole-Martin Evensen Sandness
- Oslo Service Attaches Association
- Opsund Frisør Siri Opsund
- Oscars gate 30 Eiendom AS
- Or Not To Be AS
- Oslo Bo Invest 1 AS
- Oslo Hudklinikk Hudlege Bjerke
- Onelog Norway Torvstikkeren 10 Holding AS
- Onelog Norway Regnbueveien 9 Holding AS
- Oslogruppen Av Antroposofisk Selskap i Norge
- Olert Design Av Ole-Fredrik Jansen
- Omsorgsboliger - Boliger for Eldre og Funksjonshemmede Welhavens gate Boliger