| Stor Holding AS | Administrative & support | 2019 |
| Stormyra AS | Real estate | 2022 |
| Storsnasen Management Consulting AS | Professional & scientific | 2014 |
| Stranda Spekemat AS | Professional & scientific | 2007 |
| Strengeleik AS | Information & communication | 2024 |
| Strinda Bygg AS | Construction | 2018 |
| Strinda Grunneierlag SA | Arts & recreation | 2015 |
| Strindfjord Økonomi AS | Professional & scientific | 2025 |
| Strindheim Bil Eiendom AS | Real estate | 2000 |
| Strindvegen Eiendom AS | Real estate | 2022 |
| Studmatch AS | Administrative & support | 2020 |
| Ståle Risholt Holding AS | | 2021 |
| Støhle AS | | 2020 |
| Størens Bageri AS | Arts & recreation | 2017 |
| Sunde Invest AS | Professional & scientific | 1992 |
| Superhybel AS | Real estate | 2019 |
| Superkjersti AS | Real estate | 2022 |
| Sveberg Eiendom AS | Real estate | 2025 |
| SWB AS | | 2025 |
| Søndre Eberg Gate 4 AS | Real estate | 2013 |
| T-G Elektro AS | Construction | 2018 |
| Tal Invest AS | Financial services | 2005 |
| Tannx AS | | 2020 |
| Tano-Nord Holding AS | Real estate | 2010 |
| Tas Entreprenør AS | Construction | 2019 |
| Tavek Eiendom AS | Wholesale & retail | 2012 |
| Taxi Zero AS | Transport & logistics | 2017 |
| Tbo Oralkirurgi AS | Health & social care | 2025 |
| Team Norso AS | Professional & scientific | 2021 |
| Teamkonsult AS | Professional & scientific | 2015 |
| Technocom AS | Information & communication | 2026 |
| Tegefjell Holding AS | Real estate | 2018 |
| Tekam Eiendom AS | Real estate | 2018 |
| Tekam Invest AS | Construction | 2017 |
| Teltspesialisten Eiendom AS | Administrative & support | 2007 |
| Temola Holding AS | | 2025 |
| Teoinvest AS | | 2021 |
| Tercon AS | Agriculture & fishing | 2006 |
| Tesli Invest AS | Real estate | 2001 |
| Tesliåsen AS | Real estate | 2004 |
| TGB Invest Da | Real estate | 2006 |
| TGH Investment AS | Financial services | 2005 |
| The Edit AS | Professional & scientific | 2021 |
| Theodor Overwiens Veg 6 AS | Real estate | 2023 |
| Thinkbig AS | | 2024 |
| Thomas Gundersen AS | Information & communication | 2017 |
| Thomlov Invest AS | Financial services | 2017 |
| Thul Invest AS | Real estate | 2019 |
| Ticho AS | Real estate | 2014 |
| Tidsrom AS | Administrative & support | 2013 |
| Tiger Consulting Norway Limited Nuf | Information & communication | 2010 |
| Timberbygg AS | Construction | 2019 |
| Timberbygg Holding AS | Construction | 2018 |
| Timberhill AS | | 2023 |
| Timbey Holding AS | | 2021 |
| Tinas Invest AS | Real estate | 2006 |
| Tinbuen AS | Professional & scientific | 2000 |
| Tine H. Balestrand Holding AS | | 2024 |
| Tinka AS | | 2025 |
| Tisløv-Rømo AS | Real estate | 2017 |
| TJ Consulting AS | Administrative & support | 2018 |
| Tjønnstuggu Barnehage AS | Education | 2024 |
| TM Johnsen Holding AS | | 2022 |
| Tobb Overvik 1 AS | Real estate | 2014 |
| Tobri AS | Real estate | 2005 |
| Tojem Holding AS | | 2023 |
| Tom Arntsen Holding AS | | 2014 |
| Tom Normann Holding AS | | 2023 |
| Tomta Eiendom Da | Real estate | 2000 |
| Tomu Invest AS | Real estate | 2019 |
| Torild Johansen AS | Education | 2023 |
| Torjussen Future AS | Financial services | 2021 |
| Torsheim Plass AS | Real estate | 2014 |
| Tosl AS | | 2026 |
| TQ Prosjekt AS | Wholesale & retail | 2025 |
| TQ Sport AS | Wholesale & retail | 2020 |
| Transfer AS | Administrative & support | 2017 |
| Treningsinstruktør AS | Real estate | 2011 |
| Trin - Trondheim Innovasjon AS | Professional & scientific | 2015 |
| Trines Holding AS | Financial services | 2017 |
| Trond Flatval AS | Wholesale & retail | 1994 |
| Trond Lothe Holding AS | | 2022 |
| Trondheim Betongsaging AS | Construction | 2020 |
| Trondheim Kranfører AS | Administrative & support | 2023 |
| Trondheim Liftsenter AS | Real estate | 2014 |
| Trondheim Restaurant Invest AS | Hospitality | 2015 |
| Trondheim Smådyrklinikk Eiendom AS | Real estate | 2017 |
| Trondheim Tilkomstteknikk AS | Administrative & support | 2016 |
| Trondheim Varetransport AS | Transport & logistics | 2021 |
| Trondheim-Utleie AS | Administrative & support | 2025 |
| Trøndelag Portservice AS | Construction | 2003 |
| Trønderregnskap AS | Information & communication | 2000 |
| Tusvik Invest Nuf | Information & communication | 2010 |
| Tyholt AS | Real estate | 2025 |
| Tyholtveien 79 AS | | 2022 |
| Tøb Holding AS | | 2025 |
| Tømrermester Arnstein Sørgård AS | Construction | 2002 |
| Ugla Eiendom AS | Real estate | 2025 |
| Uglastore AS | Wholesale & retail | 2024 |
| Uglem Holding AS | Real estate | 2016 |