| Sætre Nærsenter AS | Real estate | 2012 |
| Söderberg & Partners Buskerud AS | | 2026 |
| Sømrom AS | Education | 2020 |
| Søndre Kullerød 8 AS | Real estate | 1986 |
| Søndre Stiger Avløpslag | Water & waste | 2007 |
| Sønstrødfotografene AS | Professional & scientific | 1999 |
| Sørengkaia 66 AS | Real estate | 2011 |
| Sørensen Skoagenturer AS | Wholesale & retail | 2009 |
| Sørlandskjøkken Drammen AS | Wholesale & retail | 2026 |
| Sørum & Michelsen AS | Health & social care | 2026 |
| Sørvangen Næringspark AS | Health & social care | 1995 |
| Søstrenes Saks&Føn AS | Other services | 2015 |
| Søvik Investering AS | | 2026 |
| Søvik Rør AS | Construction | 2021 |
| T Bygg & Eiendom AS | Real estate | 2015 |
| T M Hansen Holding AS | Real estate | 2005 |
| T Stykket Eiendom AS | Real estate | 2009 |
| T Sørlie AS | Professional & scientific | 2023 |
| T W Nett & Data AS | Information & communication | 2008 |
| T&K Blikk AS | Construction | 2024 |
| T. Indresand Invest AS | | 2023 |
| T.E Auto AS | Wholesale & retail | 2025 |
| T.E. Lie Holding AS | | 2021 |
| T.Høvik Invest AS | | 2020 |
| T.R.M AS | Financial services | 2005 |
| Tactical Sports Group AS | Wholesale & retail | 2026 |
| Taha Eiendom AS | Real estate | 2020 |
| Taiba Kaffe AS | Wholesale & retail | 2026 |
| Tak Og Membranpartner Nuf | Construction | 2005 |
| Takmesteren AS | Construction | 2013 |
| Takringen AS | Wholesale & retail | 1984 |
| Takst & Byggkonsulent AS | Professional & scientific | 1999 |
| Takst Og Byggkompetanse AS | Professional & scientific | 2022 |
| Takst Prosjekt AS | Professional & scientific | 2000 |
| Taksthuset Viken SA | Real estate | 2022 |
| Takstteam Drammen AS | Professional & scientific | 2008 |
| Takumi Sushi AS | Hospitality | 2026 |
| Tall & Tillit AS | Professional & scientific | 2026 |
| Talsihus AS | Real estate | 1997 |
| Tamo Ans | Real estate | 1997 |
| Tandberg Akre AS | | 2025 |
| Tangen Gaard AS | | 2010 |
| Tangen Næringspark AS | Real estate | 1999 |
| Tangenkaia AS | Real estate | 2020 |
| Tangenkaia Eiendom AS | Real estate | 2020 |
| Tann Estetikk AS | Health & social care | 1999 |
| Tannhelse MSL AS | Health & social care | 2017 |
| Tannlege Brox AS | Health & social care | 2016 |
| Tannlege Espevalen AS | Health & social care | 2021 |
| Tannlege Hallgeir Ulsaker AS | Health & social care | 2016 |
| Tannlege Jon-Kjetil Reitan AS | Health & social care | 2010 |
| Tannlege Pernille AS | Health & social care | 2017 |
| Tannlege Stine Solhaug AS | Health & social care | 2017 |
| Tannlege Terje Døviken AS | Health & social care | 2003 |
| Tannlege Tom Stokke AS | Health & social care | 2015 |
| Tannlegene Sydow Og Mo AS | Health & social care | 2023 |
| Tannstudio Drammen AS | Health & social care | 2025 |
| Taora AS | Education | 2025 |
| Tarimads AS | | 2025 |
| Tarkett AB | Wholesale & retail | 1999 |
| Tarkett AS | Wholesale & retail | 1990 |
| Taste of Damascus AS | Hospitality | 2025 |
| TB Maskin AS | Wholesale & retail | 2006 |
| TBG57 AS | Real estate | 2019 |
| TBH 3 AS | Professional & scientific | 2008 |
| TC Juel AS | Professional & scientific | 2006 |
| TC Juel Holding AS | Professional & scientific | 2005 |
| TC Partner AS | Agriculture & fishing | 2008 |
| TDW Invest AS | | 2018 |
| Team Eiendom AS | Real estate | 2000 |
| Team Guddal AS | Other services | 2021 |
| Team Optometri AS | Health & social care | 2023 |
| Team Rigi AS | Education | 2026 |
| Team Tour AS | Transport & logistics | 1975 |
| Team Tour Eiendom AS | Transport & logistics | 2002 |
| TEAM3V3 AS | Professional & scientific | 2021 |
| Teamøkonomi Da | Professional & scientific | 2002 |
| Teaterkvartalet Invest AS | Real estate | 2015 |
| Techhedge Labs Ans | Information & communication | 2024 |
| Techniak AS | Professional & scientific | 2026 |
| Technicas Eiendom AS | Real estate | 2006 |
| Teekie Mobil SA | Information & communication | 2022 |
| Tefcold No AS | Wholesale & retail | 2025 |
| Tegnemaskin AS | Professional & scientific | 2017 |
| Tegulas Eiendom AS | Real estate | 2018 |
| Teigland Consult AS | Professional & scientific | 2023 |
| Tek Helse AS | Wholesale & retail | 2025 |
| Teklos AS | Information & communication | 2022 |
| Teknett AS | Information & communication | 2016 |
| Teknikas AS | | 2023 |
| Teknikkpartner AS | Wholesale & retail | 2001 |
| Tekninor AS | Construction | 2021 |
| Teknisk Isolasjon AS | Construction | 2014 |
| Teknologipartner AS | Information & communication | 2019 |
| Teko Invest AS | Real estate | 2005 |
| Teko Print & Kopi AS | Manufacturing | 1994 |
| Tekteam AS | Manufacturing | 2021 |
| Telekiosken Gulskogen AS | Wholesale & retail | 1989 |
| Telekom BTV AS | Wholesale & retail | 2015 |
| Telekom Solutions AS | Information & communication | 2024 |