| Thule Marine AS | Agriculture & fishing | 2021 |
| Thunold Holding AS | Health & social care | 1994 |
| Thuy Asia Restaurant AS | Hospitality | 2020 |
| THV54 AS | | 2022 |
| Thylo Insight AS | Information & communication | 2025 |
| Tiam Holding AS | | 2021 |
| Tibby AS | Information & communication | 2025 |
| Tibe Trondheim AS | Professional & scientific | 1996 |
| Tic Eiendomsinvest AS | Real estate | 2015 |
| Tico AS | Real estate | 1985 |
| Tida AS | | 2016 |
| Tier AS | Real estate | 2007 |
| Tigertlethix AS | Wholesale & retail | 2025 |
| Tigram Holding AS | | 2020 |
| Tilja AS | Professional & scientific | 2005 |
| Tiller Eiendom AS | | 2022 |
| Tiller Holding AS | Financial services | 2005 |
| Tiller Næringseiendom AS | Real estate | 2020 |
| Tillerbruvegen 46 AS | Real estate | 2006 |
| Tillerringen 145 AS | Real estate | 2010 |
| Tillerringen Utvikling AS | Real estate | 2017 |
| Tiltaksvegen 14 AS | Real estate | 1999 |
| Tiltaksvegen 2-4 AS | Real estate | 1982 |
| Time Expander Ventures AS | | 2020 |
| Time of Flight AS | Financial services | 2009 |
| Timeedit Norge AS | Information & communication | 2019 |
| Timelux AS | Wholesale & retail | 2022 |
| Timewalk Nuf | | 2009 |
| Timm Ventures AS | | 2026 |
| Tina 78 AS | Real estate | 2023 |
| Tina F AS | | 2024 |
| Tina Frantsen Holding AS | | 2024 |
| Tinas Hage AS | Wholesale & retail | 2021 |
| Tindboden Eiendom AS | Real estate | 2008 |
| Tindved Holding AS | | 2025 |
| Tindved II AS | Real estate | 2025 |
| Tindvik Malerservice AS | Construction | 2025 |
| Tingelstad Industries AS | | 2024 |
| Tinkabelle AS | Wholesale & retail | 2012 |
| Tiny Evil Conglomerate Holding AS | | 2019 |
| Tiol AS | Financial services | 2006 |
| Tipro Invest AS | Real estate | 1992 |
| Tjueni AS | Wholesale & retail | 2014 |
| Tjukk AS | Arts & recreation | 2014 |
| Tjukken Og Svogern AS | Transport & logistics | 2017 |
| Tjuvholmen Infrastruktur AS | Administrative & support | 2003 |
| TK Invest Ans | Real estate | 2004 |
| Tk-I Holding AS | | 2024 |
| Tkfrost Holding AS | | 2024 |
| Tkvalen Holding AS | | 2024 |
| TKX Drift AS | Construction | 2012 |
| TL Accounting AS | Professional & scientific | 2016 |
| TM Autoinvest AS | Wholesale & retail | 2020 |
| TM Bjørnaas Invest AS | | 2021 |
| TM Gruppen AS | Real estate | 2005 |
| Tmi Turbo Machinery Institute AS | Real estate | 2003 |
| Tmmetal Invest AS | Real estate | 1989 |
| TMT Drift Da | Health & social care | 2022 |
| Tmts AS | Real estate | 2020 |
| TMW AS | | 2019 |
| TN Data AS | Information & communication | 2014 |
| Tnanalyse AS | Information & communication | 2017 |
| Tnbd Holding AS | Real estate | 2020 |
| To Do Nordics AS | Administrative & support | 2020 |
| To Kokker Selskapsmat AS | Hospitality | 1994 |
| To Prosjektrådgivning AS | Professional & scientific | 2019 |
| To Sølvmynter Film AS | Information & communication | 2014 |
| Toath Holding AS | Real estate | 2019 |
| Tobb Boligbygg AS | Real estate | 2012 |
| Tobb Byggdrift AS | Administrative & support | 2002 |
| Tobb Energi AS | Professional & scientific | 2023 |
| Tobb Fosslia AS | Real estate | 2013 |
| Tobb Hylle 3 AS | Real estate | 2025 |
| Tobb Hylle 4 AS | Real estate | 2025 |
| Tobb Overvik 2 Utbygging AS | Real estate | 2020 |
| Tobi Holding AS | Wholesale & retail | 2021 |
| Todder Holding AS | | 2010 |
| Toffer Invest AS | Real estate | 2012 |
| Toftesund AS | Professional & scientific | 2013 |
| Toftin AS | Wholesale & retail | 2018 |
| Tog 9 AS | Real estate | 2021 |
| Tohawi AS | | 2020 |
| Tokas AS | Financial services | 2015 |
| Token AS | Hospitality | 2026 |
| Tokhos AS | Financial services | 2001 |
| Tokle AS | Hospitality | 2005 |
| Tokle Invest AS | | 2025 |
| Toksnes Invest AS | | 2025 |
| Tolar AS | Information & communication | 2026 |
| Tollboden Eiendom Drammen AS | Real estate | 2001 |
| Tollbua AS | Hospitality | 2023 |
| Tom Kjeldsberg Holding AS | | 2024 |
| Toma Consulting AS | Construction | 2020 |
| Tomahawk II AS | Real estate | 2015 |
| Tomaka AS | Professional & scientific | 2017 |
| Tomas Langlo Holding AS | | 2017 |
| Tomatosharp AS | Other services | 2020 |
| Tomjor Drift AS | Real estate | 2022 |
| Tomjor Holding AS | | 2026 |
| Tommen Gram Holding AS | Real estate | 1996 |