| MLG Hold AS | | 2025 |
| MM Dansekurs Da | Education | 2009 |
| MM Live Art AS | Arts & recreation | 2024 |
| Mobman AS | Professional & scientific | 2020 |
| Mobman Holding AS | Professional & scientific | 2018 |
| Mokabier Invest AS | | 2022 |
| Monika Ciesla-Strauss AS | Health & social care | 2022 |
| Monika Taxi AS | Transport & logistics | 2024 |
| Monsoon Import AS | Wholesale & retail | 2014 |
| More Valves AS | Professional & scientific | 2016 |
| Morgendagens Helter AS | | 2021 |
| Morrot 826 Holding AS | | 2023 |
| Morten Knudsen AS | Professional & scientific | 2025 |
| Mos Ember AS | Hospitality | 2022 |
| Mosbøen AS | Financial services | 2005 |
| Moss Invest AS | Real estate | 2017 |
| Mower Spesialisten AS | Wholesale & retail | 2006 |
| Mulle AS | Wholesale & retail | 1989 |
| Munch Invest AS | | 2021 |
| MWK AS | Arts & recreation | 2019 |
| My Holiday Life AS | Administrative & support | 2025 |
| Nabus AS | Information & communication | 2015 |
| Nadderud Arena AS | Real estate | 2012 |
| Nadderud Autosenter AS | Wholesale & retail | 2001 |
| Nadderud Park AS | Real estate | 2020 |
| Nadderudlia Holding AS | | 2021 |
| Nangilima AS | Financial services | 2019 |
| Nari Konsult AS | Professional & scientific | 2002 |
| Navigator AS | | 2020 |
| Nayook AS | Professional & scientific | 2019 |
| Nec Eiendom AS | Real estate | 1994 |
| Nedrelo Invest AS | | 2021 |
| Negard Invest AS | Real estate | 2001 |
| Nemus Bekkestua AS | Health & social care | 2019 |
| Nen Tømrer & Snedkerservice | Construction | 1998 |
| Nettinvest AS | | 2025 |
| Nextnet AS | Real estate | 2000 |
| Nha Konsulenttjenester AS | Professional & scientific | 2021 |
| Nik Invest AS | Financial services | 2022 |
| Nikoline Anundsen AS | Professional & scientific | 2022 |
| Nils W Koren AS | Financial services | 2005 |
| Nina Malz AS | Professional & scientific | 2020 |
| Nira Venture AS | | 2025 |
| Nirana Holding AS | | 2021 |
| Nist Invest AS | Professional & scientific | 2024 |
| Niza Invest AS | | 2012 |
| NMH Holding AS | Health & social care | 2024 |
| Noble Grapes AS | Wholesale & retail | 2024 |
| Noble Wines AS | Wholesale & retail | 2021 |
| Noob Holding AS | | 2022 |
| Noor Concept AS | Wholesale & retail | 2012 |
| Noraco Norway Ltd Nuf | Wholesale & retail | 2007 |
| Noraq Inventus AS | Professional & scientific | 2021 |
| Norcard AS | Information & communication | 1997 |
| Nordhaug AS | Real estate | 2014 |
| Nordhaug Drift AS | Real estate | 2025 |
| Nordic E-Commerce AS | Wholesale & retail | 2020 |
| Nordic Energy Company AS | Real estate | 1982 |
| Nordic Explorer AS | Wholesale & retail | 2018 |
| Nordic Wagen AS | Wholesale & retail | 2022 |
| Nordiske Byggesystemer AS | Real estate | 2023 |
| Nordsnora AS | Administrative & support | 2025 |
| Norges Toppidrettsgymnas Bærum AS | Education | 2006 |
| Norges Toppidrettsgymnas Trondheim AS | Education | 2024 |
| Norges Toppidrettsgymnas Ungdomsskole Bærum AS | Education | 2006 |
| Norgus AS | Real estate | 2017 |
| Norsk Forsikringsmegling AS | | 1990 |
| Norsk Profilreklame & Gaver AS | Professional & scientific | 2010 |
| Northern Farmhouse Capital AS | Real estate | 2018 |
| Northstone AS | Professional & scientific | 2026 |
| Norway Marine Insurance AS | Professional & scientific | 2002 |
| Norwegian Architects AS | Professional & scientific | 1990 |
| Nosotola Invest AS | Professional & scientific | 2018 |
| Nozomi Invest AS | | 2024 |
| NPT Norway Protravel GmbH | Administrative & support | 2015 |
| Nuikala AS | | 2020 |
| Nye Nordveien 43 AS | Real estate | 2017 |
| Nyrud Finans AS | Professional & scientific | 2005 |
| O a Halvari AS | | 1995 |
| O. Grønvold Holding AS | | 2024 |
| Obrascón Huarte Lain S.A. Nuf | Construction | 2015 |
| Octopus AS | Professional & scientific | 1971 |
| Ocular AS | Real estate | 2007 |
| Odela Holding AS | Financial services | 2012 |
| Oden Investment AS | | 2021 |
| Olav Velde AS | Real estate | 1921 |
| Oldpaps AS | Professional & scientific | 2017 |
| Olithe AS | Wholesale & retail | 2020 |
| Oliviers & Co Norway AS | Wholesale & retail | 2016 |
| Onkel Tor AS | Financial services | 2014 |
| Opb Holding AS | Financial services | 2015 |
| Opp Invest AS | Professional & scientific | 2021 |
| Opra Eiendom AS | Real estate | 2010 |
| Optimal Invest AS | Financial services | 2013 |
| Oreco AS | Real estate | 2013 |
| Orepa AS | Real estate | 2014 |
| Origo Financial Partners AS | Professional & scientific | 2011 |
| Ortoptist Klinikken AS | Health & social care | 2024 |
| Oslo Marine Tech AS | Wholesale & retail | 2026 |
| Oslo Næringsmegling AS | Real estate | 2026 |