| Tomo Investering AS | Professional & scientific | 2006 |
| Tomorrowland AS | Real estate | 2021 |
| Tomteutvikling 45 AS | Real estate | 2008 |
| Tomteutvikling AS | Real estate | 2026 |
| Tone Consulting AS | Professional & scientific | 2020 |
| Tone Haave AS | Education | 2022 |
| Tone of Investment AS | | 2025 |
| Tone of Leadership AS | Professional & scientific | 2025 |
| Tone Tandrevold AS | Manufacturing | 2016 |
| Tonje AS | | 2022 |
| Tonstad Næringspark AS | Real estate | 2026 |
| Tools Are Us AS | Wholesale & retail | 2014 |
| Toolserv AS | Mining & quarrying | 2007 |
| Top Capi AS | Real estate | 2020 |
| Top of Mind AS | Professional & scientific | 2019 |
| Top Shelf AS | Professional & scientific | 2008 |
| Topdon Norge AS | Wholesale & retail | 2024 |
| Topp Frisør AS | Other services | 2002 |
| Topp Sopp AS | Agriculture & fishing | 2019 |
| Topp Stemning AS | Information & communication | 2016 |
| Toppanker AS | Administrative & support | 2017 |
| Tor Bjarne Asheim AS | Transport & logistics | 2002 |
| Tor Strandhus Consult Nuf | Professional & scientific | 2021 |
| Tor Strandhus Consulting AS | Professional & scientific | 2026 |
| Tor Sølve Tjelta AS | Health & social care | 2020 |
| Tor Tech AS | Professional & scientific | 2026 |
| Torbergsen Holding AS | Professional & scientific | 2014 |
| Tore Askeland Holding AS | | 2005 |
| Tore Invest AS | | 2024 |
| Tore Sunde Alarm AS | Wholesale & retail | 2017 |
| Tores Kunst & Rammer AS | Wholesale & retail | 2000 |
| Torfjell Invest AS | Wholesale & retail | 2005 |
| Torfæus AS | Real estate | 2024 |
| Torgeir Larsen AS | Professional & scientific | 2020 |
| Torger Carlsens Gate AS | Real estate | 2024 |
| Torgersens Invest AS | | 2025 |
| Torgro AS | | 2025 |
| Torgterrassen AS | Real estate | 2021 |
| Torhild Veslemøy Riisdal AS | Health & social care | 2021 |
| Torjussen Eiendom AS | Real estate | 1967 |
| Torjussen Holding AS | Construction | 2005 |
| Torneroseveien 5 AS | Real estate | 1986 |
| Toro Rabioso AS | Wholesale & retail | 2007 |
| Torq/Lite Europe AS | Professional & scientific | 2014 |
| Tors Eiendom AS | Real estate | 1998 |
| Tortellini Holding AS | | 2023 |
| Torunn Høyland AS | Financial services | 1998 |
| Torvet 7 AS | Real estate | 2000 |
| Torvet 7 B AS | Real estate | 2001 |
| Tos Holding AS | Hospitality | 2022 |
| Tost Holding AS | | 2026 |
| Tosten Ans | Professional & scientific | 1999 |
| Total AS | Real estate | 2013 |
| Total Bolig & Nærings Service AS | Real estate | 2016 |
| Total E&P Angola SA | Professional & scientific | 2000 |
| Total E&P Congo S.A. | Mining & quarrying | 2006 |
| Total Home AS | Construction | 2020 |
| Total Pharma AS | | 2017 |
| Total Service Partner AS | Information & communication | 1999 |
| Total Upstream Nigeria Ltd | Administrative & support | 2014 |
| Totale Tjenester AS | Construction | 2019 |
| Totalenergies Ep Gass Handel Norge AS | Wholesale & retail | 2005 |
| Totalenergies Ep Norge AS | Mining & quarrying | 1977 |
| Totalenergies Marketing Norge AS | Wholesale & retail | 1989 |
| Totsa Totalenergies Trading SA | Wholesale & retail | 2003 |
| Tou City AS | Construction | 2012 |
| Tou Helsepark AS | Health & social care | 2024 |
| Tou Næringspark AS | Real estate | 1997 |
| Tou Park Næringseiendom AS | Real estate | 2010 |
| Tou Parkering AS | Transport & logistics | 2012 |
| Tou Scene AS | Arts & recreation | 2002 |
| Toucheart AS | Wholesale & retail | 2023 |
| Towerbells AS | Real estate | 2023 |
| Tp-Holding AS | | 2005 |
| Trace Team AS | Professional & scientific | 2011 |
| Track Tech AS | Information & communication | 2017 |
| Trade Tech AS | Mining & quarrying | 2001 |
| Trafikk Holdco AS | | 2023 |
| Trafikkskole Holdco AS | Education | 2024 |
| Train Smart Project AS | Education | 2025 |
| Training and Consulting Ans | Professional & scientific | 1990 |
| Trallfa AS | Professional & scientific | 2006 |
| Tranberg Invest AS | Professional & scientific | 2004 |
| Trane Invest AS | | 2026 |
| Transocean Barents ASA | Mining & quarrying | 2005 |
| Transocean Norway Operations AS | Mining & quarrying | 2006 |
| Transocean Offshore (North Sea) Ltd Nuf | Mining & quarrying | 1997 |
| Transocean Services AS | Transport & logistics | 1999 |
| Transocean Spitsbergen ASA | Administrative & support | 2005 |
| Trattoria Testa Rossa AS | Hospitality | 2018 |
| Travbaneveien 3 Forus AS | Real estate | 2005 |
| TRB Capital AS | Wholesale & retail | 2023 |
| Tre Og Stål AS | Wholesale & retail | 1983 |
| Treca AS | | 1994 |
| Trehus Byggfornyelse AS | Construction | 2021 |
| Trehus Eiendom AS | Real estate | 2021 |
| Trekk 2509 AS | | 2025 |
| Trekk 2603 AS | | 2026 |
| Trekk 2604 AS | | 2026 |
| Trekk 2605 AS | | 2026 |