| Traveldoktor AS | Health & social care | 2014 |
| Tre Spesial AS | Manufacturing | 1996 |
| Treff Gruppen AS | | 2024 |
| Treinert AS | Real estate | 2014 |
| Trend Consulting AS | Information & communication | 2024 |
| Treningsgleder AS | Arts & recreation | 2024 |
| Tres Cobres AS | Water & waste | 2017 |
| Tretun 1 AS | Administrative & support | 2005 |
| Trex AS | Real estate | 2020 |
| Triara Da | Other services | 2018 |
| Triathlonpro | Education | 2014 |
| Trimit No AS | Information & communication | 2016 |
| Trinkle AS | | 2020 |
| Trinord Holding AS | | 2025 |
| Trmd Holding AS | | 2025 |
| Troll Bil AS | Wholesale & retail | 2025 |
| Trolltinden Advokater Sandefjord AS | Professional & scientific | 2018 |
| Tron O. Kløw AS | Real estate | 2005 |
| Truong Invest AS | Professional & scientific | 2018 |
| Try Advisory AS | Professional & scientific | 2020 |
| Trydal Eiendom AS | | 2024 |
| Trydal Holding AS | Construction | 2022 |
| Trygg Helseklinikk AS | Health & social care | 2026 |
| Trygg Økonomi AS | Education | 1998 |
| Trysilfjell Resort AS | Hospitality | 2025 |
| Tråkk T AS | | 2022 |
| TT Food AS | Hospitality | 2022 |
| Tta Utleie AS | Administrative & support | 2026 |
| Tundøren AS | Wholesale & retail | 1971 |
| Tuntec AS | Wholesale & retail | 2020 |
| Turan Byggtjenester AS | Construction | 2019 |
| TV8 Studio AS | Information & communication | 2026 |
| Tvebol Eiendom AS | Real estate | 2016 |
| Tveitan Furuheim AS | | 2022 |
| Tveitan Invest AS | Real estate | 2019 |
| Tveitan Maskinutleie AS | Administrative & support | 2021 |
| Tveiten & Riis Murmesterfirma AS | Construction | 1997 |
| Tvelu Eiendom AS | Real estate | 2005 |
| Tvistein Bidco AS | | 2023 |
| Twig AS | Real estate | 2005 |
| Twkongsvold AS | Wholesale & retail | 2026 |
| Tyrkiafryd Ferieleiligheter AS | Real estate | 2014 |
| Tyrolerhus AS | Construction | 2003 |
| Tyrolerhus Invest AS | Real estate | 1992 |
| Tåka Holding AS | Financial services | 2012 |
| Tøhf Eiendom AS | Real estate | 2022 |
| Tøhf Holding AS | Real estate | 2022 |
| Tømrer Anders Ask AS | Construction | 2007 |
| Tømrer Atle Larsen AS | Construction | 2024 |
| Tømrer Bjørn Wiik AS | Construction | 2018 |
| Tømrer F. Engelstad AS | Construction | 2024 |
| Tømrer Glenn Tomas Berentsen AS | Construction | 2020 |
| Tømrer Hafredal AS | Construction | 2022 |
| Tømrer Håkonsen AS | Construction | 2025 |
| Tømrer Jens Thomas Jensen AS | Construction | 2017 |
| Tømrer Jonas Lien Holm AS | Construction | 2017 |
| Tømrer Knut Ingar Nalum AS | Construction | 2022 |
| Tømrer Knut-Øivind Bruun AS | Construction | 2014 |
| Tømrer Max Marius Myklebust AS | Construction | 2019 |
| Tømrer Sandstad AS | Construction | 2024 |
| Tømrer Stangeby AS | Construction | 2017 |
| Tønsberg Eiendomsinvest AS | Real estate | 2017 |
| Tønsberg Gressbane AS | Real estate | 1908 |
| Tønsberg Kontoreiendom AS | Real estate | 2024 |
| U24 Holding AS | | 2024 |
| U4 Service AS | Administrative & support | 2024 |
| Ula Ship Management AS | | 2022 |
| Ulvestad - Vangen Eiendom AS | Real estate | 2022 |
| Ulvestad - Vangen Holding AS | Real estate | 2022 |
| Ulvestad Hold AS | | 2022 |
| Ulvestad Psykologtjenester AS | Health & social care | 2020 |
| Ulvin Berg Holding AS | Professional & scientific | 2016 |
| Umbra Produkter AS | Manufacturing | 1986 |
| Umbra Solskjerming AS | Manufacturing | 2005 |
| Uncertain States Scandinavia Da | Wholesale & retail | 2015 |
| Understellservice AS | Other services | 2013 |
| Undringshuset AS | Information & communication | 2024 |
| Unefai AS | Information & communication | 2025 |
| Ungula AS | Agriculture & fishing | 2026 |
| Unicall Sandefjord AS | Real estate | 2007 |
| Unike Fjordhoteller AS | Real estate | 2019 |
| Unike Hoteller AS | Professional & scientific | 2016 |
| Unike Hoteller Eiendom AS | Real estate | 2021 |
| Unike Hoteller Restaurant AS | Hospitality | 2022 |
| Unike Midtåsen AS | Hospitality | 2018 |
| Unique Experience AS | Real estate | 2023 |
| Unique Hotels AS | Hospitality | 2012 |
| University AS | Wholesale & retail | 1989 |
| Unix Eiendom AS | Wholesale & retail | 2005 |
| Unix Holding AS | Wholesale & retail | 2005 |
| Unwasted AS | Wholesale & retail | 2024 |
| Uranienborgveien 1 AS | Real estate | 2013 |
| Urbant Design AS | | 2021 |
| Urder Invest AS | Financial services | 2016 |
| Utleiemegleren Vestfold AS | Real estate | 2019 |
| V F Eiendom AS | Real estate | 1966 |
| Vadder Kapital AS | Financial services | 2013 |
| Vajra AS | Professional & scientific | 2025 |
| Valdr Invest AS | | 2025 |
| Valdras Bygg AS | Construction | 2014 |