| Jensehaugen Consulting AS | Information & communication | 2013 |
| Jensen Auto AS | Wholesale & retail | 2021 |
| Jensen Investment AS | | 2023 |
| Jenseninvest AS | | 2020 |
| Jerstad VVS AS | Construction | 2022 |
| Jes Holding AS | Real estate | 2016 |
| Jesse AS | Real estate | 1999 |
| Jesse Finans AS | Real estate | 2010 |
| Jesse Setesdal AS | Real estate | 2010 |
| Jet Kapital AS | | 2026 |
| Jevan Butikkdrift AS | Hospitality | 2021 |
| Jevan Stasjonsdrift AS | Wholesale & retail | 2021 |
| Jfa Holding AS | Real estate | 2017 |
| JFK Eyewear AS | Professional & scientific | 2020 |
| JFP Services AS | Professional & scientific | 2016 |
| JH Auto Invest AS | Other services | 2024 |
| Jha Holding AS | Real estate | 2005 |
| JHM Invest AS | | 2015 |
| Jia Investment | Hospitality | 2019 |
| Jiffy International AS | Manufacturing | 1977 |
| Jiffy Products International AS | Manufacturing | 1958 |
| Jimme Invest AS | Real estate | 2017 |
| JJ Beauty AS | Wholesale & retail | 2025 |
| JJ- Service AS | Administrative & support | 2014 |
| JJJ Konsulenttjenester AS | Professional & scientific | 2005 |
| JJK Holding AS | Other services | 2014 |
| JJK Solsenterdrift AS | Other services | 2009 |
| Jjo AS | | 2025 |
| JK Frisør AS | Other services | 2022 |
| JKG Invest AS | | 2021 |
| JKK Invest AS | Real estate | 2023 |
| JKN Holding AS | | 2022 |
| JL Drift AS | Administrative & support | 2025 |
| JL Gruppen AS | Wholesale & retail | 2005 |
| JLM Holding AS | | 2021 |
| Jloka AS | | 2024 |
| JMD Invest AS | Real estate | 2005 |
| JMT Consulting AS | Professional & scientific | 2026 |
| Jmødegaard Holding AS | Construction | 2022 |
| JND Holding AS | Real estate | 2025 |
| Jnft Eiendom AS | Real estate | 2022 |
| Jnft Holding AS | Health & social care | 2022 |
| Joachim Nygaard AS | Real estate | 2017 |
| Joadan AS | Financial services | 2012 |
| Joar-S Bygg AS | Construction | 2023 |
| Jobb+ AS | Real estate | 2019 |
| Jobs Invest AS | Professional & scientific | 2018 |
| Jobygg AS | Construction | 2024 |
| Joco Consulting AS | Professional & scientific | 2024 |
| Jodasol AS | Professional & scientific | 2022 |
| Joha Invest AS | Real estate | 2016 |
| Johan Finnestad AS | | 2025 |
| Johan G Olsen AS | Manufacturing | 1998 |
| Johansen Investment AS | | 2022 |
| John Øydna Holding AS | Health & social care | 2005 |
| Johnny Puma AS | Real estate | 2016 |
| Johns Bar AS | Hospitality | 2005 |
| Johnsen & Li AS | Wholesale & retail | 2024 |
| Johnsen & Olaussen Da | Health & social care | 1999 |
| Johnsen Taxidrift Ans | Transport & logistics | 2004 |
| Johnsen Technology AS | Information & communication | 2024 |
| Joi Holding AS | | 2026 |
| Join Nordics AS | Professional & scientific | 2026 |
| Jolama Holding AS | | 2021 |
| Jom Invest AS | | 2024 |
| Jomaas Import & Co Da | Wholesale & retail | 1984 |
| Jomi Eiendom AS | Professional & scientific | 1985 |
| Jon AS | Professional & scientific | 1998 |
| Jon Blund AS | Professional & scientific | 1966 |
| Jono AS | Health & social care | 2005 |
| Jopro AS | Administrative & support | 2020 |
| Jordbærpikene Sandens AS | Hospitality | 2013 |
| Jordhøy AS | Wholesale & retail | 2026 |
| Jostein Hauge Holding AS | Real estate | 2000 |
| Jpe Eiendom AS | Real estate | 2025 |
| Jpe Invest AS | Arts & recreation | 2005 |
| JPS Landmåling AS | Professional & scientific | 2020 |
| JPT Consulting AS | Information & communication | 2020 |
| JR Bygg AS | Construction | 2022 |
| JR Management AS | Real estate | 2007 |
| Jre 1 AS | Real estate | 2023 |
| JRM Holding AS | Real estate | 2011 |
| Jry Holding AS | | 2025 |
| JS Ship Invest AS | | 2023 |
| Jse Import AS | Wholesale & retail | 2011 |
| JSH Holding & Consulting AS | Professional & scientific | 2016 |
| JSL - Holding AS | Administrative & support | 2024 |
| JSL Restaurantdrift AS | Health & social care | 2009 |
| JSP Utvikling AS | | 2024 |
| JT Selected AS | Professional & scientific | 2018 |
| Ju Invest AS | Professional & scientific | 2005 |
| Juce Holding AS | | 2023 |
| Jud AS | Other services | 2026 |
| Judys Atelier AS | Manufacturing | 2016 |
| Juice Consulting AS | Professional & scientific | 2019 |
| Juklerød-Multiservice AS | Transport & logistics | 2024 |
| Jul Invest AS | Real estate | 2006 |
| Julia MH Invest AS | | 2022 |
| Juliusskogen AS | Real estate | 2025 |
| Jumate Holding AS | Financial services | 2017 |