| Oust Holding AS | Oslo | 1997 |
| Out of Bounds Hamar AS | Hamar | 2021 |
| Outdoor Finnskogen AS | Lundersæter | 2019 |
| Outdoor Norway AS | Voss | 2016 |
| Outotec Turula OY | Fi-83500 Outokump | 2016 |
| Outsourcing Company | Ytre Enebakk | 2024 |
| Ov Facilty Services AS | Oslo | 2025 |
| Ovation Events GmbH | De-81825 München | 2023 |
| Ove Invest AS | Inderøy | 2013 |
| Oveland Hageservice AS | Froland | 2020 |
| Oveland Utemiljø AS | Froland | 2002 |
| Over Norm AS | Sogndal | 2019 |
| Overens Utvikling AS | Lillehammer | 2004 |
| Overgaard-Manpower | Son | 2011 |
| Overhalla Renhold AS | Overhalla | 2019 |
| Overhallsvegen 818 AS | Skage I Namdalen | 2021 |
| Overland Group AS | Oslo | 2020 |
| Overlat AS | Lillestrøm | 2026 |
| Overseas AS | Orre | 2022 |
| Overvoll AS | Oslo | 2017 |
| Owayy | Dk-1054 Copenhagen K | 2022 |
| Owl 3 AS | Oslo | 2024 |
| Owl 6 AS | Oslo | 2024 |
| Oxford Computer Group Limited | Oxfordshire Ox25 4Al | 2012 |
| Oxford Global Resources | Cork City | 2010 |
| Oxford Recruitment Pty Ltd Nuf | Oslo | 2022 |
| Oxitrate AS | Drøbak | 2004 |
| Oxxy Group PLC | 1075 Nicosia | 2016 |
| OY Doratone AB | Fi-22100 Mariehamn | 2010 |
| Oü Europersonal | 10124 Tallin | 2010 |
| Oü Mööbliproff | Ee-86604 Paikuse Vald Pärnumaa | 2014 |
| P & P Facility Services AS | Sandnes | 2013 |
| P O Executive AS | Røyneberg | 1987 |
| P S Express & Utleie AS | Årland | 2024 |
| P&L Service AB | 66131 Säffle | 2012 |
| P&M Netherlands B.V. Norway Branch | 1724Bj Oudkarspell | 2022 |
| P&O Vikarer AS | Nittedal | 2021 |
| P&P Construction S.R.O. | Sk-010 01 Zilina | 2019 |
| P&P Drift 1 AS | Laksevåg | 2016 |
| P-Air AB | Se-553 35 Jönköping | 2023 |
| P-H Nilsen Holding AS | Rådal | 2005 |
| P. Levik AS | Tolvsrød | 2013 |
| P.A. Eiendomsservice AS | Frogner | 2017 |
| P.P.H.U Pecherzewski Waldemar Pecherzewski | Pl-86-065 Lochowo | 2015 |
| P.R-B Izobud-Rem Jan Horoszkiewicz | Pl-66 400 Gorzow Wielkopolski | 2006 |
| P.Stiil AS | Oslo | 2020 |
| P/E Strategic Partners AS | Oslo | 2010 |
| P/F Zenith Offshore | Fo-710 Klaksvik | 2014 |
| P2P Rent AS | Nykirke | 2017 |
| P2P Service AS | Oslo | 2025 |
| Pabben AS | Birkeland | 2018 |
| Packovation AS | Åros | 2004 |
| Paddy Sportsreiser AS | Aurskog | 2010 |
| Padel Red Hamjern AS | Hamar | 2017 |
| Padelzone Nodeland AS | Nodeland | 2021 |
| Padmos Grondverzet En Kraanverhuur | 4254 Xp Sleeuwijk | 2017 |
| Paese AS | Oslo | 2023 |
| Pahs Holding AS | Hafrsfjord | 2011 |
| Pair Finance Norway AS | Oslo | 2026 |
| Paixao Maintenances AS | Oslo | 2024 |
| Pal AS | Sandefjord | 2019 |
| PALAEO7 LLP | Buckinghamshire Hp22 4Lw | 2018 |
| Palazzo Norway AS | Grimstad | 2016 |
| Pallidus AS | Bjoa | 2020 |
| Pallmyre Reisebyrå AS | Hafslundsøy | 2017 |
| Palmark Offshore AS | Stavanger | 2001 |
| Palmer Brands AS | Oslo | 2012 |
| Palmereiser AS | Drammen | 2026 |
| Palouse AS | Tromsø | 2004 |
| Palrental AS | Skedsmokorset | 2023 |
| Pamelle AS | Ellingsøy | 2025 |
| Pan Service AS | Løten | 2024 |
| Panda Academy AS | Oslo | 2025 |
| Panda Invest & Services AS | Kjeller | 2018 |
| Pangea Resoursing Limited | London Sw6 5Nh | 2012 |
| Pangea Rocks Constructions Aps | Dk-6800 Varde | 2013 |
| Pangeo Subsea Scotland Ltd | Aberdeen Ab32 6Fl Scotland | 2011 |
| Panorama Hjemmetjenester AS | Skien | 2020 |
| Panoramagården AS | Olden | 2025 |
| Pantufla Invest AS | Oslo | 2021 |
| Pap Stavanger AS | Bryne | 2016 |
| Pap Stavanger Holding AS | Bryne | 2015 |
| Pappbuene Produksjon Og Service AS | Lillesand | 2019 |
| Paradise International Service AS | Drammen | 2012 |
| Paradisreiser AS | Svelvik | 2005 |
| Paraply Media AS | Laksevåg | 2017 |
| Parbulkers III AS | Oslo | 2015 |
| Parc Aviation Limited | Dublin 9 | 2013 |
| Parchem V AS | Oslo | 2023 |
| Parcon Ix AS | Oslo | 2024 |
| Pardive Subsea AS | Oslo | 2021 |
| Pareto Bassøe Shipbrokers AS | Oslo | 2001 |
| Paribus Deutsche Eisenbahn Renditefonds XV GmbH & Co. KG Nuf | De-22767 Hamburg | 2024 |
| Parin AS | Stavanger | 2021 |
| Park & Anleggstjenester AS | Trondheim | 1998 |
| Park & Eiendomsdrift AS | Solbergelva | 2022 |
| Park Amusement Drift AS | Haslum | 2016 |
| Park Drift AS | Kokstad | 2017 |
| Park Event AS | Skien | 2013 |
| Park Holding AS | Haslum | 2016 |