| THF Holding AS | | 2020 |
| Thingbø Rørservice AS | Construction | 2021 |
| Think Invest AS | Professional & scientific | 2018 |
| Third Space AS | Real estate | 2026 |
| Thitech AS | Information & communication | 2022 |
| Thjf Eiendom AS | Real estate | 2023 |
| Thomas Haugland Holding AS | | 2022 |
| Thoralf Myhre AS | Construction | 1977 |
| Thordal Produksjon Og Design AS | Arts & recreation | 2019 |
| Thore S Rovik AS | Real estate | 1967 |
| Thrustme Norway AS | Professional & scientific | 2025 |
| Thu Betong AS | Real estate | 1966 |
| Thu Holding AS | Real estate | 2022 |
| Thu Tre, Stein Og Byggevare AS | Wholesale & retail | 2007 |
| Tidewater Marine AS | Transport & logistics | 1972 |
| Tidewater Norge AS | Transport & logistics | 1997 |
| Tidewater Rederi AS | Transport & logistics | 1997 |
| Tidewater Seabed Shipping AS | Administrative & support | 2008 |
| Tidlig Trygghet AS | Health & social care | 2025 |
| Tiksa AS | Professional & scientific | 2022 |
| Tilbords AS | Wholesale & retail | 2016 |
| Time Aluminium AS | Manufacturing | 2004 |
| Time Gruppen AS | Real estate | 2020 |
| Time Interiør AS | Manufacturing | 2008 |
| Timeloggen AS | Information & communication | 2019 |
| Timesave AS | Professional & scientific | 1987 |
| Timmo AS | Real estate | 1998 |
| Tin & Tial AS | Hospitality | 2024 |
| Tina Bjørlo Advokat AS | Professional & scientific | 2022 |
| Tinkam Nuf | Professional & scientific | 2009 |
| Tinker AS | Information & communication | 2022 |
| Tipp Topp Holding AS | | 2022 |
| Tippo AS | Professional & scientific | 2013 |
| Tippo Media AS | Professional & scientific | 2013 |
| Tipåti AS | Real estate | 2017 |
| Tireb AS | | 2021 |
| Tiro M&A Holding AS | Construction | 2023 |
| Titlius AS | Construction | 2016 |
| Titsand AS | Real estate | 2024 |
| Tjessem & Joa Holding AS | Real estate | 2024 |
| Tjessem Og Lillebø AS | Mining & quarrying | 2023 |
| Tjessheim AS | | 2019 |
| Tjessi.No AS | Wholesale & retail | 2016 |
| Tjora Consulting AS | Professional & scientific | 2024 |
| TJS AS | | 2024 |
| Tjø Invest AS | Financial services | 2006 |
| Tjørhom AS | Transport & logistics | 2024 |
| Tjørhom Drift AS | Other services | 2026 |
| Tjøstheim & Co AS | | 2020 |
| Tjøtta B29 AS | Real estate | 2023 |
| TK Brukt AS | Wholesale & retail | 2013 |
| TK Kyllingstad AS | Hospitality | 2024 |
| TK Rørleggerservice AS | Construction | 2017 |
| TK Sandnes AS | Professional & scientific | 2008 |
| TKN Holding AS | Wholesale & retail | 2016 |
| TLB Rådgivning Holding AS | Professional & scientific | 2024 |
| TLP Invest AS | | 2020 |
| TM - Holding AS | Financial services | 2005 |
| TM Byggservice AS | Construction | 2020 |
| TM Kos AS | Financial services | 2005 |
| TM Raugstad Holding AS | | 2017 |
| Tmed AS | Education | 2021 |
| TMG Invest AS | Professional & scientific | 2018 |
| TMS Meisland Invest AS | Real estate | 2020 |
| TMS Support AS | Professional & scientific | 2012 |
| Tmyrslo Invest AS | Real estate | 2016 |
| TNB Kvadrat AS | Wholesale & retail | 2021 |
| TNB Maxi AS | Wholesale & retail | 2021 |
| Tni Holding AS | | 2025 |
| Tno | Professional & scientific | 2014 |
| TNT Håra Holding AS | | 2025 |
| TNX AS | | 2024 |
| To - Ma Studio AS | Professional & scientific | 2021 |
| To Hold Or Not to Holding AS | | 2021 |
| To Holding AS | Real estate | 2005 |
| To På AS | Professional & scientific | 2024 |
| Toberget AS | | 2020 |
| Tocavima AS | Administrative & support | 2020 |
| Todnem AS | Agriculture & fishing | 2023 |
| Todnem Investering AS | | 2023 |
| Todnem Samdrift Da | Agriculture & fishing | 2000 |
| Tofte Print AS | Professional & scientific | 2026 |
| Toggdog AS | | 2024 |
| Togklager AS | Professional & scientific | 2021 |
| Tolaas Invest AS | Professional & scientific | 2026 |
| Tollefsen AS | Wholesale & retail | 2005 |
| Tolo Invest AS | Financial services | 2011 |
| Tom K. Riis Invest AS | Wholesale & retail | 2017 |
| Tomlin Holding AS | Professional & scientific | 2018 |
| Tomt Eidsvollgata 53 AS | Real estate | 2022 |
| Tomte Holding AS | Real estate | 2018 |
| Tomteareal AS | Real estate | 2012 |
| Tonje Pedersen AS | Professional & scientific | 2026 |
| Tools Vagle AS | Wholesale & retail | 2006 |
| Toon Capital AS | | 2025 |
| Top Dog Akademiet AS | Education | 2021 |
| Top Man AS | Wholesale & retail | 1982 |
| Top Man Eiendom AS | Real estate | 2021 |
| Topp Arrangement AS | Administrative & support | 2013 |
| Tor Gunnar Næss AS | Construction | 1987 |