| Trige Invest AS | | 2023 |
| Triko AS | Real estate | 2005 |
| Triko Holding AS | Real estate | 2023 |
| Trilobitten AS | Real estate | 2025 |
| Trima Brøyting AS | Administrative & support | 2019 |
| Triplefood AS | Hospitality | 2024 |
| Trippy Ventures AS | Administrative & support | 2023 |
| Trojan AS | Real estate | 2003 |
| Trojo Invest AS | Financial services | 2013 |
| Trollbu 165 AS | | 2023 |
| Trollhavn Holding AS | | 2026 |
| Trollhøgda AS | Real estate | 2019 |
| Troma Company AS | Real estate | 1987 |
| Troma Eiendommen AS | Real estate | 2024 |
| Troman Holding AS | | 2021 |
| Trombo AS | Real estate | 2013 |
| Troms Bygg & Vedlikehold AS | Construction | 2019 |
| Troms Byggforvaltning AS | Administrative & support | 2016 |
| Troms Byggmontering AS | Construction | 2003 |
| Troms Eiendom AS | | 2012 |
| Troms Eiendomsmegling AS | Real estate | 2024 |
| Troms Elektro AS | Construction | 2015 |
| Troms Holding AS | Energy | 2019 |
| Troms Hus AS | Real estate | 1994 |
| Troms Kystfisk AS | Agriculture & fishing | 2025 |
| Troms Logopedtjeneste AS | Health & social care | 2019 |
| Troms Losseservice AS | Transport & logistics | 2000 |
| Troms Maritime Automation AS | Construction | 2024 |
| Troms Og Finnmark Taxi AS | Transport & logistics | 2022 |
| Troms Optik AS | Wholesale & retail | 2001 |
| Troms Portservice AS | Construction | 2003 |
| Troms Reiseliv AS | Administrative & support | 2003 |
| Troms Takst AS | Professional & scientific | 1997 |
| Tromso Coco Apartments AS | Hospitality | 2021 |
| Tromso Drive AS | Administrative & support | 2025 |
| Tromso Things to Do AS | Administrative & support | 2025 |
| Tromso Wonders AS | Administrative & support | 2024 |
| Tromsolove AS | Administrative & support | 2024 |
| Tromsopp AS | Agriculture & fishing | 2021 |
| Tromstech Da | Information & communication | 1992 |
| Tromsø Accessible Tours AS | Administrative & support | 2020 |
| Tromsø Adventures AS | Administrative & support | 2025 |
| Tromsø Agency AS | Wholesale & retail | 2022 |
| Tromsø Airport Hotel AS | Real estate | 1996 |
| Tromsø Akvakulturpark AS | Agriculture & fishing | 2023 |
| Tromsø Arctic Skimo AS | Arts & recreation | 2024 |
| Tromsø Art and Green Living AS | Hospitality | 2025 |
| Tromsø Assistanse AS | Transport & logistics | 2001 |
| Tromsø Autolakk AS | Other services | 1989 |
| Tromsø Bagasjeservice AS | Transport & logistics | 2025 |
| Tromsø Bakeri AS | Manufacturing | 2000 |
| Tromsø Bakeri Eiendom II AS | Real estate | 2018 |
| Tromsø Bakeri Holding AS | Real estate | 2018 |
| Tromsø Barnefestival AS | Arts & recreation | 2021 |
| Tromsø Bergsprenging AS | Construction | 2018 |
| Tromsø Betong Team AS | Construction | 2018 |
| Tromsø Bil & Båtelektro AS | Other services | 1987 |
| Tromsø Billakkering AS | Other services | 1987 |
| Tromsø Bilpleiesenter AS | Other services | 2025 |
| Tromsø Bilredning 24/7 AS | Transport & logistics | 2017 |
| Tromsø Bilstereo AS | Wholesale & retail | 2016 |
| Tromsø Bilutleie AS | Administrative & support | 2019 |
| Tromsø Blomsterbinderi AS | Wholesale & retail | 2023 |
| Tromsø BNB AS | Hospitality | 2024 |
| Tromsø Bolig AS | Real estate | 2015 |
| Tromsø Boligutleie AS | Real estate | 2020 |
| Tromsø Brøyting AS | Administrative & support | 2023 |
| Tromsø Bud Og Catering Da | Transport & logistics | 1996 |
| Tromsø Budbil Sentral AS | Transport & logistics | 1996 |
| Tromsø Buldresenter AS | Arts & recreation | 2021 |
| Tromsø Bygg & Tre Ans | Construction | 2025 |
| Tromsø Carbon Capture AS | Professional & scientific | 2022 |
| Tromsø Drift AS | Wholesale & retail | 2017 |
| Tromsø Eiendom AS | Real estate | 2014 |
| Tromsø Eiendomshjelp AS | Real estate | 1987 |
| Tromsø Eiendomsmegling AS | Real estate | 2021 |
| Tromsø Eiendomsutvikling AS | Real estate | 1997 |
| Tromsø Elektro AS | Construction | 1996 |
| Tromsø Elektronikkbutikk AS | Wholesale & retail | 2023 |
| Tromsø Emarked AS | Wholesale & retail | 2020 |
| Tromsø Event Service Da | Professional & scientific | 2004 |
| Tromsø Farvehandel Hafa AS | Wholesale & retail | 1992 |
| Tromsø Film AS | Information & communication | 2012 |
| Tromsø Fiskeindustri AS | Manufacturing | 2009 |
| Tromsø Forsikring AS | Professional & scientific | 2013 |
| Tromsø Forsikringssenter AS | Financial services | 2022 |
| Tromsø Fremleie AS | Hospitality | 2025 |
| Tromsø Frisør AS | Other services | 2016 |
| Tromsø Frisørdrift AS | Other services | 2014 |
| Tromsø Fysioterapi AS | Health & social care | 2015 |
| Tromsø Gift & Souvernir Shop 2 AS | Wholesale & retail | 2026 |
| Tromsø Gift & Souvernir Shop AS | Wholesale & retail | 1999 |
| Tromsø Gjestehus AS | Real estate | 2016 |
| Tromsø Golfsenter AS | Arts & recreation | 2025 |
| Tromsø Gullsmedforretning AS | Wholesale & retail | 1991 |
| Tromsø Gulv AS | Construction | 2022 |
| Tromsø Helse- Og Idrettsklinikk AS | Real estate | 2021 |
| Tromsø Hobbykeramikk Da | Wholesale & retail | 1997 |
| Tromsø Håndverksservice AS | Construction | 2008 |
| Tromsø Hårstudio AS | Other services | 2012 |