Bedrift O - Sagene
- Ojs AS
- Olowo
- Orange AS
- Opigen AS
- Omnivor AS
- Oviá AS
- Onsøien
- Osloclubcast DA
- Oddur Joensen
- Olimb Rådgivning
- Oslo Boligselskap AS
- Oslo Eiendomsselskap AS
- Odd Klippenvåg
- Objektiv Forlag AS
- Ole Roen
- Oslo Malerservice AS
- Ognøy Invest AS
- Ovino Berg
- Ole Mofjell
- Olsen Produksjon
- Odor Veis
- Olav Vestlie
- Oslo Rørteknikk AS
- Oskarsen Communication
- Olav Aartun
- Oslo Eiendomskompani AS
- Otsu Sushi AS
- Oslo Recordings ANS
- Otterdal Design
- Oslo Sandvolleyballklubb
- Ophrys Invest AS
- Oslo Skateboardforening
- Oslo Skateboardforening
- Omar Trans
- Oslomet Poker
- Oscar Thue
- Olimb Scenekunstvirksomhet
- Oslo Middelalderfestival
- O. Øye
- Oslo Meditasjon
- Olve Haugen
- Ordrett Ordkontor ANS
- Omstilling Sagene
- Oslo Hageservice
- Ola Hedstein
- Osjord Insights AS
- Osjord Eiendom AS
- Olus Born
- Oda Djuplasti
- Oppikaaken Business Ventures DA
- Ove Siljan II AS
- Oana-Nicoleta Antonescu
- Oonda - Marie Payan
- Origin Sol Productions AS
- Oslo Brewing Company AS
- Oslo Brewing Company AS
- Oslo Software Architecture
- Oslo Brewing Company AS
- Oda Kristin Tjoflot
- Oslo Ideology Lab
- Oslo Ideology Lab
- Olsson Christian Høgetveit
- One Night Only
- Os Said Taxi
- O Baldan Consult
- Omdahl Cool Co.
- Obv Venture i AS
- Oslo Packraft Klubb
- Oslo Packraft Klubb
- Oleks Iversen / Shturmov
- Outofboredom Bård Falch Gundersen
- Oslo Tomte og Eiendomsutvikling AS
- Osteopat Natalie J. Nesshaug
- Oliva Renhold Olgerts Kozlovs
- Oslo Bolig og Eiendomsutvikling AS
- Ocean Peer Magnus Osmundsvaag
- Ofiriha William Logai Ochieng
- Orthodont Laboratoriet Gro Walde
- Orange Mini Senter Mansour
- Oslo Rørteknikk Tomas Vascila
- Oftestadwriting Bernt Torvild Oftestad
- Ordo AB Chao Mark Francombe
- Ole Rasmus Bjerke, Bratsj
- Osteopat Helene V. Ausland
- One-Eyed Cat Drefvelin
- Oppegaard Sigurd Martin Nordli
- Ovrum Lys og Scene
- Oslo Feiermester Alf Pettersen
- Oslo Tak & Bygg Fredriksen
- Offentlig Godkjent Fotterapeut Astrid Brænd
- Oslo 32 Kfuk-Kfum-Speidere
- Oslo English Academy Madalynne Rose Frary
- Operakollektivet - Klassisk Sang Opera og Event Patrick Egersborg