| Sørensen Blikkenslagerverksted AS | Construction | 2017 |
| Sørensens Byggeinnredning Ans | | 1990 |
| Sørinvest AS | Real estate | 1987 |
| Sørlie Øre Nese Hals AS | Health & social care | 2020 |
| Sørvendt Eiendom AS | Real estate | 2012 |
| Søstrene Ingebrigtsen AS | Wholesale & retail | 2005 |
| T & T Holding AS | Real estate | 2004 |
| T T Management AS | Professional & scientific | 1987 |
| T to AS | Wholesale & retail | 2004 |
| T.B. Eiendom AS | | 2013 |
| T.J Invest AS | Real estate | 2026 |
| T10 Invest AS | Real estate | 2011 |
| Ta Sats Consulting AS | | 2023 |
| Tabulaterra AS | Information & communication | 2026 |
| Tacky Kaffekompani AS | Wholesale & retail | 2026 |
| Tag-Eiendom AS | Real estate | 2024 |
| Tag-Holding AS | Real estate | 2024 |
| Tah Storkjøkkenservice AS | Other services | 2012 |
| Tak & Metall AS | Wholesale & retail | 1994 |
| Tak & Metall Eiendom AS | Real estate | 1997 |
| Tak & Metall Invest AS | Wholesale & retail | 2005 |
| Tak Og Boligservice AS | Construction | 2018 |
| Takst & Byggkontroll AS | Professional & scientific | 2018 |
| Taksthuset Nord AS | Real estate | 2018 |
| Tales of Thule AS | Hospitality | 2025 |
| Tangmelen AS | Real estate | 1997 |
| Tangs Eiendom Ans | Real estate | 1997 |
| Tangs Restaurant AS | Hospitality | 1990 |
| Tanja Wilhelmsen Holding AS | | 2020 |
| Tank Design Tromsø AS | Professional & scientific | 2002 |
| Tankestrøm AS | Arts & recreation | 2023 |
| Tannhelseklinikken Tromsø AS | Health & social care | 1997 |
| Tannlege Camilla Bomstad AS | Health & social care | 2013 |
| Tannlege Elsa Sundsvold AS | Health & social care | 2000 |
| Tannlege Guro Møller AS | Health & social care | 2013 |
| Tannlege Hans Are Ovanger AS | Health & social care | 2000 |
| Tannlege Kari-Mette Andersen AS | Health & social care | 2004 |
| Tannlege Kjærstad AS | Health & social care | 2006 |
| Tannlege Lidvard Hjørungnes AS | Health & social care | 2024 |
| Tannlege Morten Øye AS | Health & social care | 2012 |
| Tannlege Sandra Marie Jakobsen AS | Health & social care | 2014 |
| Tannlege Tom Ellingsen AS | Health & social care | 2002 |
| Tannlege Urd Lilleng AS | Health & social care | 2014 |
| Tannlegespesialistene AS | Health & social care | 2005 |
| Tannvik AS | Real estate | 2018 |
| Tao Eiendom AS | Real estate | 2005 |
| Tapas Tromsø AS | Hospitality | 2012 |
| Taraldsen Holdings AS | | 2026 |
| Taste Tromsø AS | Hospitality | 2025 |
| Tasty Catering AS | Hospitality | 2026 |
| Tasty Foodhouse AS | Administrative & support | 2024 |
| Tave Invest AS | Real estate | 1990 |
| Taxi Nord AS | Transport & logistics | 2022 |
| TB Regnskap AS | Professional & scientific | 1998 |
| TBD Invest AS | Financial services | 2010 |
| Tbe Ankenesveien 150 AS | Real estate | 2023 |
| Tbe Botnhågveien 33 AS | Real estate | 2012 |
| Tbe Fagernesveien 139 AS | Construction | 2016 |
| Tbe Haraldvollveien 2 AS | Real estate | 2019 |
| Tbe Skattørvegen 50 AS | Real estate | 2010 |
| Tbe Stangnesterminalen 1 AS | Real estate | 2014 |
| Tbe Strandgata 60 AS | Real estate | 2018 |
| TBT Bolig AS | Real estate | 2012 |
| TBT Invest AS | Construction | 2018 |
| TBT Næring AS | Real estate | 2020 |
| TD Tank AS | Transport & logistics | 2026 |
| Team Invest Nord AS | Real estate | 2020 |
| Team Tempel Da | Information & communication | 2000 |
| TEAM2 Eiendom AS | Real estate | 2004 |
| Tec Eiendom AS | Real estate | 2016 |
| Techbev AS | Real estate | 2020 |
| Technor Energy AS | Energy | 2001 |
| Technoservice AS | Manufacturing | 2012 |
| Tee Tromsø AS | Hospitality | 2026 |
| Tegne & Byggeservice AS | Professional & scientific | 1985 |
| Teigen Invest Og Holding AS | | 2024 |
| Teknel AS | Construction | 2017 |
| Teknisk Bureau AS | Wholesale & retail | 1970 |
| Teknisk Bureau Engros AS | Manufacturing | 1971 |
| Teknisk Forvaltning Og Drift AS | Real estate | 2023 |
| Teknisk-Service AS | Wholesale & retail | 2005 |
| Tekstil Consult AS | Wholesale & retail | 2017 |
| Tekstvilje AS | Professional & scientific | 2025 |
| Telekom AS | Administrative & support | 2022 |
| Telepartner AS | Manufacturing | 1989 |
| Teleport AS | Transport & logistics | 2023 |
| Telli Group AS | | 2025 |
| Telli Ventures AS | Wholesale & retail | 2023 |
| Tellicherry AS | Information & communication | 2015 |
| Tenari AS | Professional & scientific | 2014 |
| Termar AS | Financial services | 2009 |
| Terminalgata 1 AS | Real estate | 2014 |
| Terminalgata 114 AS | Real estate | 2014 |
| Terminalgata 38 AS | Real estate | 2019 |
| Terminalgata 44-70 AS | Real estate | 2017 |
| Tersus Renhold AS | Administrative & support | 2008 |
| Testnor AS | Professional & scientific | 2021 |
| Tett På Regnskap & Rådgivning AS | Professional & scientific | 2022 |
| Tewiik Holding AS | | 2020 |
| TG Næringseiendom AS | Real estate | 2014 |