| J H J AS | Construction | 2005 |
| J&T Bygg AS | Construction | 2020 |
| J&T Homeservice AS | Administrative & support | 2023 |
| J. Lorentzen Holding AS | | 2026 |
| J.Haugen AS | | 2005 |
| J.R. Eiendom AS | Real estate | 2021 |
| J.R. Hansen Holding AS | Real estate | 2023 |
| J.Thoresen AS | | 2019 |
| Ja Med AS | Health & social care | 2021 |
| Jacob Friis Ur-Optikk AS | Wholesale & retail | 2005 |
| Jacobs AS | Real estate | 1987 |
| Jadefjord AS | | 2025 |
| Jag Restaurants AS | Hospitality | 2019 |
| Jagu AS | Real estate | 2005 |
| Jakh Holding AS | | 2022 |
| Jan Seiring Holding AS | Financial services | 2017 |
| Janhugo AS | Information & communication | 2025 |
| Jannike Invest AS | | 2019 |
| Jansen Reklame AS | Manufacturing | 1987 |
| JDD Music AS | Arts & recreation | 2013 |
| Jeanett Kraukle Andreassen AS | Health & social care | 2026 |
| Jeanette Hammer Holding AS | | 2022 |
| Jeh Konsult AS | Health & social care | 2014 |
| Jekta Butikkdrift AS | Wholesale & retail | 2012 |
| Jekta Gull Og Ur AS | Wholesale & retail | 2012 |
| Jekta Specsavers AS | Wholesale & retail | 2022 |
| Jektapizza AS | Hospitality | 2009 |
| Jel Eiendom AS | Real estate | 2020 |
| Jensen Elektriske AS | Construction | 1988 |
| Jensenmedia AS | Professional & scientific | 2024 |
| Jenssen Ventures AS | Construction | 2023 |
| Jernbanen Tromsø AS | Real estate | 1997 |
| Jetrondsen Eiendom AS | Real estate | 2016 |
| Jgi Consulting AS | Professional & scientific | 2020 |
| Jgi Invest AS | Wholesale & retail | 2020 |
| Jgi Investering AS | | 2008 |
| JHK Trafikkskole AS | Education | 2016 |
| Jhts Holding AS | Real estate | 2023 |
| JKP Holding AS | | 2013 |
| JKW Holding AS | | 2025 |
| JM Hansen Eiendom AS | Real estate | 2015 |
| JM Hansen Gruppen AS | Construction | 2026 |
| JM Hansen Holding AS | Construction | 1986 |
| JM Hansen Nord AS | Construction | 2010 |
| JM Maskin & Transport AS | Construction | 2023 |
| Jm-Holding AS | Construction | 2022 |
| JML Invest AS | Professional & scientific | 2026 |
| Joakim Abrahamsen Eftf AS | Real estate | 1972 |
| Jobb I Nord AS | Administrative & support | 2006 |
| Jobb Og Fritid AS | Wholesale & retail | 2020 |
| Joda Invest AS | | 2023 |
| John D Breivoll AS | Professional & scientific | 1987 |
| John Kristoffersen Arkitektkontor AS | Professional & scientific | 1989 |
| Johnsen Holding AS | Real estate | 2002 |
| Johnsen Rekruttering Og Rådgivning AS | Administrative & support | 2021 |
| Johs Iversen AS | Real estate | 1990 |
| Jonte Holding AS | Real estate | 2014 |
| Jordbærpikene Jekta AS | Hospitality | 2012 |
| Jordbærpikene Nerstranda AS | Hospitality | 2009 |
| Jordobservasjon AS | Professional & scientific | 2021 |
| Jorvik AS | Real estate | 2018 |
| Josef Bamba AS | Arts & recreation | 2016 |
| Jotopp Holding AS | | 2019 |
| Jovia AS | Wholesale & retail | 2026 |
| JP Management AS | Professional & scientific | 2017 |
| JPB AS | Real estate | 2019 |
| JS Johansen Holding AS | | 2021 |
| JTT AS | Financial services | 2009 |
| Jubra AS | | 2019 |
| Julie Johnsen AS | Professional & scientific | 2013 |
| Juliussen Eiendom AS | Real estate | 2021 |
| Junosando Bygg AB | Administrative & support | 1997 |
| Jupiter Business Partner AS | Information & communication | 2021 |
| Jupiter Consulting AS | Information & communication | 2022 |
| Jupiter Eiendom AS | Real estate | 2005 |
| Jupiter System Partner AS | Information & communication | 1988 |
| Just AS | Professional & scientific | 2018 |
| Jørn Antonsen Holding AS | Real estate | 2019 |
| K Hvidsten Holding AS | Professional & scientific | 2021 |
| K Mydland Holding AS | Manufacturing | 2017 |
| K&P Proff Tjenester AS | Construction | 2016 |
| K. M. Dahl Invest AS | Real estate | 2005 |
| K. M. Dahl Tromsø AS | Real estate | 1996 |
| K.Ringberg Kran Og Transport AS | Transport & logistics | 2006 |
| K24 Prestasjon AS | Other services | 2016 |
| K24 Tromsø Nord AS | Health & social care | 2025 |
| K9SHOP AS | Wholesale & retail | 2023 |
| Kad Capital AS | | 2025 |
| Kae-Holding AS | | 2021 |
| Kaf-Ra AS | Professional & scientific | 2024 |
| Kaffebønna AS | Hospitality | 1998 |
| Kaffemester'N Tromsø AS | Wholesale & retail | 2005 |
| Kaffesystemer AS | Wholesale & retail | 2011 |
| Kaia 11 AS | Hospitality | 2011 |
| Kaia Legesenter AS | Health & social care | 2004 |
| Kaikan AS | Construction | 2016 |
| Kaion AS | Real estate | 2017 |
| Kaldslett AS | Real estate | 1991 |
| Kaldslett Panorama AS | Real estate | 2017 |
| Kaldslettneset AS | Real estate | 2013 |