| Tallak Holding AS | | 2026 |
| Tallglede AS | Real estate | 2012 |
| Tallglede Holding AS | | 2020 |
| Tallglede Regnskap Da | Professional & scientific | 2012 |
| Tame Holding AS | Construction | 2017 |
| Tan AS | | 2025 |
| Tandberg Eiendom Avdeling Agrokvartalet AS | Real estate | 2016 |
| Tandberg Eiendom Avdeling Bellevue AS | Real estate | 2016 |
| Tandberg Eiendom Avdeling Elvely Heggedal AS | Real estate | 2014 |
| Tandberg Eiendom Avdeling Heggedal Fabrikker AS | Real estate | 2016 |
| Tandberg Eiendom Avdeling Munkesletta 3 AS | Real estate | 2016 |
| Tandberg Eiendom Avdeling Sentrumsgården Heggedal AS | Real estate | 2014 |
| Tandberg Eiendom Avdeling Strøket 1 Og 3 AS | Real estate | 2016 |
| Tandberg Eiendom Avdeling Strøket 5, 7 Og 9 AS | Real estate | 2016 |
| Tandberg Eiendom Avdeling Tofte AS | Real estate | 2016 |
| Tandberg Eiendom Avdeling Torvveien 1 AS | Real estate | 2016 |
| Tandberg Eiendom Avdeling Torvveien 7 AS | Real estate | 2016 |
| Tandberg Eiendom Avdeling Trafo AS | Real estate | 2016 |
| Tandberg Eiendom Parkering AS | Transport & logistics | 2015 |
| Tang-Jonstad Holding AS | | 2026 |
| Tangen & Karlsen Rep Service Ans | | 1989 |
| Tango Consulting AS | Professional & scientific | 2025 |
| Tanish Investments AS | Financial services | 2014 |
| Tannglede Hovda AS | Health & social care | 2013 |
| Tannlege Geir Olsen AS | Health & social care | 2019 |
| Tannlege Helge Ravik AS | Health & social care | 1997 |
| Tannlege Marie Fjærtoft Heir AS | Health & social care | 2020 |
| Tansons Eiendom AS | Real estate | 2023 |
| Tape Holding AS | | 2025 |
| Tata Communications (Nordic) AS | Information & communication | 2003 |
| TB Norge | Construction | 2020 |
| Tca Holding AS | Financial services | 2005 |
| Tdeco AS | Administrative & support | 2022 |
| Team Iver AS | Education | 2023 |
| TEAMSUPPORT1 AS | Wholesale & retail | 2021 |
| TEAMSUPPORT1 Holding AS | Wholesale & retail | 2021 |
| Teartumbler AS | | 2026 |
| Teas Energi AS | Energy | 2014 |
| Tebla AS | Professional & scientific | 2005 |
| Tech Holding AS | Information & communication | 2021 |
| Techno Innovation AS | Professional & scientific | 1994 |
| Techseed Edge AS | Professional & scientific | 2022 |
| Tegnova AS | Professional & scientific | 2025 |
| Teien Rørservice AS | Construction | 2005 |
| Tekkor AS | Administrative & support | 2026 |
| Telespor AS | Wholesale & retail | 2004 |
| Tempura House Adv. Skøyenåsen AS | Hospitality | 2026 |
| Tempura House Avd. Asker AS | Hospitality | 2025 |
| Tenebrio Holding AS | | 2025 |
| Tenold Visionary Company AS | | 2026 |
| Teradata Norge AS | Information & communication | 2007 |
| Terapil AS | Health & social care | 2019 |
| Terp AS | Administrative & support | 2026 |
| Tet Invest AS | Real estate | 1969 |
| Tett & Rent Coating Asker AS | Construction | 2026 |
| TF2NULL AS | | 2025 |
| The Backup AS | | 2022 |
| The Club House AS | Other services | 2024 |
| The Farmer AS | Real estate | 2011 |
| The Hitchhikers Da | Arts & recreation | 2019 |
| The Nordic Mellow AS | Arts & recreation | 2019 |
| The Shift Collective AS | Education | 2025 |
| Thelka Holding AS | | 2024 |
| Theodor Hjelmtveit Holding AS | | 2025 |
| Thermoconsult AS | Professional & scientific | 1992 |
| Thermotech Private Equity AS | Real estate | 2008 |
| Thers Holding AS | Real estate | 2012 |
| Theta AS | Information & communication | 2022 |
| Thevik Invest AS | Financial services | 2012 |
| Thfor 119 Holding AS | | 2023 |
| Thiis Eiendomsutvikling AS | Real estate | 2014 |
| Thinn Logistics AS | Professional & scientific | 2012 |
| Thinq AS | Information & communication | 2018 |
| Thomas Bruun Holding AS | Financial services | 2018 |
| Thor B Olsen AS | Information & communication | 1987 |
| Thor Håkstad AS | Administrative & support | 2012 |
| Thoruud Holding AS | Financial services | 2015 |
| Ti Marine Contracting AS | Manufacturing | 2000 |
| Ti Mo Invest AS | Financial services | 2015 |
| TI2 Finans AS | Administrative & support | 2016 |
| Tideman Marine AS | Professional & scientific | 2021 |
| Tidio AS | Wholesale & retail | 2018 |
| Tigeni AS | Information & communication | 2018 |
| Tiki Navigator AS | Information & communication | 2004 |
| Tind Ventures AS | | 2023 |
| Tindberg Holding AS | | 2023 |
| Tippi AS | Information & communication | 2025 |
| Tito Consulting AS | Financial services | 2024 |
| Tito Eiendom AS | Real estate | 2021 |
| Tittan Invest AS | | 2022 |
| Tiur Frisør AS | Other services | 2016 |
| Tix Invest AS | Arts & recreation | 2021 |
| Tix Music AS | Arts & recreation | 2022 |
| TJM Bygg AS | Construction | 2021 |
| TKS Invest AS | Financial services | 2005 |
| TMF Norway AS | Professional & scientific | 2006 |
| TML Holding AS | Education | 2021 |
| TMS & Sønner Invest AS | Real estate | 2008 |
| TN Bygg Og Bad AS | Construction | 2021 |
| TNB Asker AS | Wholesale & retail | 2013 |