| TV 26 Eiendom AS | Real estate | 2017 |
| TV Trøndelag AS | Information & communication | 2024 |
| TVC Investments AS | | 2022 |
| Tvete Holding AS | Real estate | 1977 |
| Tvi Tvi Da | Wholesale & retail | 2000 |
| Tvinnereim Studios AS | Information & communication | 2025 |
| Tvo Invest AS | | 2024 |
| Twelve Parsecs Holding AS | Financial services | 2017 |
| Twin Media AS | Information & communication | 2022 |
| TWT Wavold Trading AS | Wholesale & retail | 1987 |
| Ty Tannklinikk AS | Health & social care | 2011 |
| Ty Tannklinikk Holding AS | Health & social care | 2022 |
| Tycho Space Technologies AS | Information & communication | 2022 |
| Tyd AS | Information & communication | 2012 |
| Tyd Corp AS | Information & communication | 2026 |
| Tyd Holding AS | | 2026 |
| Tyholt Eiendom AS | Real estate | 2024 |
| Tyholttunet Barnehage SA | Education | 2023 |
| Tyholttårnet AS | Real estate | 2013 |
| Tyholtveien 63A AS | Real estate | 2024 |
| Tynset Energipark AS | | 2025 |
| Tynset Infrastruktur AS | Professional & scientific | 2025 |
| Type IT AS | Manufacturing | 2003 |
| Tyrirot AS | | 2025 |
| Tål AS | | 2024 |
| Tårnrestauranten Galaksen AS | Hospitality | 1988 |
| Tæller AS | Hospitality | 2025 |
| Tøff AS | Real estate | 2006 |
| Tømmerholtet AS | Real estate | 2005 |
| Tømmrerfirma Kvarsnes AS | Construction | 2000 |
| Tømrer Og Forskalingsservice AS | Construction | 2011 |
| Tømrerknilsen AS | Construction | 2025 |
| Tønor AS | Hospitality | 2025 |
| U-Swing Da | Arts & recreation | 2012 |
| U. Unneberg Holding AS | | 2022 |
| UA13 Holding AS | | 2022 |
| Uas Service AS | Professional & scientific | 2016 |
| Ubiq Aerospace AS | Professional & scientific | 2017 |
| Ucon AS | Professional & scientific | 1996 |
| Udelt AS | Information & communication | 2023 |
| Udelt Holding AS | Information & communication | 2023 |
| Ugelstad Holding AS | Professional & scientific | 2015 |
| Ugla Nærsenter AS | Real estate | 2021 |
| Uglabekken AS | Manufacturing | 2005 |
| Uglakiosken AS | | 2019 |
| Uhoda AS | Professional & scientific | 2023 |
| Ulf Eide AS | Information & communication | 2019 |
| Ulla Bolig AS | Real estate | 2020 |
| Ulleberg & Rosvold Ans | Administrative & support | 2001 |
| Ullådalsstugan AS | Real estate | 2018 |
| Uls AS | Real estate | 2014 |
| Ulset-Eiendom AS | Wholesale & retail | 2006 |
| Ulstad Eiendom AS | Real estate | 1979 |
| Ulstad Holding AS | Real estate | 2005 |
| Ultra Bygg AS | Construction | 2016 |
| Ulula Capital AS | | 2025 |
| Ulvan Eiendom AS | Real estate | 2001 |
| Ulvan Personal AS | Administrative & support | 1996 |
| Ulvan Ship Management AS | Transport & logistics | 2020 |
| Ulven Scene AS | Arts & recreation | 2025 |
| Ulvund Invest AS | | 2020 |
| Uma AS | | 2022 |
| Un-Told AS | Wholesale & retail | 2021 |
| Undo AS | Health & social care | 2015 |
| Undoqo AS | Information & communication | 2023 |
| Unicare Coperio AS | Health & social care | 2002 |
| Unilift Norge AS | Wholesale & retail | 2016 |
| Unilodge AS | Real estate | 2021 |
| Union VVS AS | Construction | 2022 |
| Uniq AS | Wholesale & retail | 2013 |
| Uniq Garn AS | Wholesale & retail | 2020 |
| Uniq Invest AS | Education | 2020 |
| Uniqum AS | Professional & scientific | 2005 |
| United Transport SK AS | Transport & logistics | 2022 |
| Unitek AS | Construction | 2020 |
| Unity Living AS | Real estate | 2024 |
| Unna Gohas AS | | 2019 |
| Unne Invest AS | Real estate | 2007 |
| Uno Invest AS | Real estate | 2014 |
| Uno-X Eiendom Holding AS | Real estate | 2008 |
| Unocom AS | Information & communication | 2001 |
| Unocum AS | Professional & scientific | 2017 |
| Upgrade AS | Wholesale & retail | 2026 |
| Upnorth Film AS | Information & communication | 2017 |
| Upnorth Film Trondheim AS | Information & communication | 2004 |
| Uppercut Film AS | Information & communication | 1996 |
| Upstream Risk Management AS | Professional & scientific | 2014 |
| Uptime Da | Information & communication | 1999 |
| Urmaker Lian AS | Wholesale & retail | 2024 |
| Urmaker Næss AS | Wholesale & retail | 1998 |
| Urologiklinikken Trondheim AS | Health & social care | 2016 |
| Ursus 1 AS | | 2020 |
| Ursus 2 AS | | 2020 |
| Ursus Eiendom AS | Real estate | 2006 |
| Ursus Holding AS | Professional & scientific | 2015 |
| Ursus Invest AS | Real estate | 2015 |
| Ursus Silence AS | Manufacturing | 2021 |
| Ursus Taftøyan AS | | 2024 |
| Ursus Toppco Holding AS | | 2023 |
| Usakova Bud AS | Transport & logistics | 2021 |