| Strømme Holding AS | | 2025 |
| Stubben Holding AS | Real estate | 2006 |
| Studenthjelp Privatundervisning AS | Education | 2014 |
| Studio Blend AS | Other services | 2019 |
| Studio S Hårdesign AS | Other services | 1991 |
| Stødig Forlag AS | Education | 2025 |
| Støe AS | Real estate | 2017 |
| Summerhill RD AS | | 2025 |
| Sun. G. Holding AS | Real estate | 2005 |
| Sundberg Holding AS | | 2025 |
| Sundbyfoss Eiendom AS | Real estate | 2018 |
| Sundstredet City AS | Real estate | 2020 |
| Sunna Holding AS | | 2019 |
| Surf & Soul AS | Manufacturing | 2023 |
| Sushi-Teria Moss AS | Hospitality | 2026 |
| Svea Rekkverk AS | Construction | 2015 |
| Svein Andreassen AS | Real estate | 1994 |
| Svein Andreassen Holding AS | Real estate | 2005 |
| Svein Kristoffersen AS | Real estate | 2016 |
| Svellando Holding AS | | 2021 |
| Sven Holding AS | Construction | 2005 |
| Svenberg Invest AS | Financial services | 2021 |
| Sventhobygg AS | Real estate | 2002 |
| Swe AS | Construction | 2005 |
| Sy- Og Strikkedilla AS | Wholesale & retail | 2007 |
| Sykkelforum AS | Information & communication | 2017 |
| Symfonia AS | Health & social care | 2025 |
| Synsenteret Moss AS | Wholesale & retail | 2006 |
| Syrrist Karosseri AS | Other services | 2001 |
| System Flyttebyrå AS | Water & waste | 2017 |
| Sæbyhagen AS | Real estate | 2014 |
| Sæmab Norge AS | Professional & scientific | 1994 |
| Søndagsmarkedet AS | Real estate | 2021 |
| Søndre Jeløy Invest AS | Real estate | 2016 |
| Sørby Invest AS | | 2020 |
| Sørensen Elektronikk AS | Professional & scientific | 2014 |
| Sørlie Media AS | Information & communication | 2022 |
| Søstrene Hjelseth AS | Real estate | 2014 |
| Søstrene Systue AS | Manufacturing | 2017 |
| T M Fisk Og Skalldyr Ans | Hospitality | 1998 |
| T Sundby AS | Financial services | 2016 |
| T&D Design AS | Wholesale & retail | 2019 |
| Tabletopbattle AS | Wholesale & retail | 2016 |
| Taboo AS | Hospitality | 2021 |
| Taisto Tuunanen Svets O Industriservice AB | Manufacturing | 1999 |
| Tak & Vedlikehold AS | Construction | 1993 |
| Take the Reins - Equestrian Training AS | Education | 2012 |
| Takova AS | Professional & scientific | 2017 |
| Talentwise AS | Professional & scientific | 2020 |
| Tallom AS | Financial services | 2006 |
| Tamanna AS | | 2024 |
| Tanker Engineering AS | Professional & scientific | 1979 |
| Tannféen Norge AS | Health & social care | 2013 |
| Tannhauser Gate AS | Information & communication | 1989 |
| Tannlege Andreas Klette AS | Health & social care | 2018 |
| Tannlege His AS | Health & social care | 2025 |
| Tannlege Moja AS | Health & social care | 2018 |
| Tannlege Roar Hovland AS | | 1995 |
| Tannlege Shokooh Mohandesnia AS | Health & social care | 2026 |
| Tannmannen Holding AS | Health & social care | 2020 |
| Tannpleier Synne Antonsen AS | Health & social care | 2023 |
| Tannstein AS | Real estate | 2005 |
| Tannverket Moss AS | Health & social care | 2005 |
| Tapirypo AS | Hospitality | 2021 |
| Tara Media Torunn Pettersen AS | Arts & recreation | 2018 |
| Tarento AS | Professional & scientific | 2019 |
| Target Eiendom AS | Real estate | 2015 |
| TAXI4 AS | Transport & logistics | 2013 |
| Tayseer AS | Wholesale & retail | 2025 |
| TB Hill 2 Holding AS | | 2023 |
| Tbob Holding AS | | 2026 |
| TCM Capital AS | | 2019 |
| TD Rent AS | Wholesale & retail | 2008 |
| Tea Time Tango AS | Wholesale & retail | 1986 |
| Team Eurosko AS | Wholesale & retail | 2015 |
| Team Installasjon AS | Construction | 1983 |
| Tech Aware Gaming AS | Information & communication | 2020 |
| Techne Ans | Information & communication | 1999 |
| Technotrade AS | Wholesale & retail | 2013 |
| Tecno X AS | Wholesale & retail | 2026 |
| Tectonic AS | Professional & scientific | 2026 |
| Tegnepartner AS | Professional & scientific | 2010 |
| Tehagen AS | Wholesale & retail | 2013 |
| Tekst & Tekstil AS | Professional & scientific | 2014 |
| Telekiosken Moss AS | Wholesale & retail | 1998 |
| Telemeny AS | Information & communication | 2015 |
| Tellus Trading AS | Professional & scientific | 2015 |
| Tema Eiendomsutvikling AS | Real estate | 2005 |
| Temoss Eiendom AS | Real estate | 2016 |
| Tempranillo AS | Real estate | 1993 |
| Temt AS | | 2005 |
| Tenens AS | | 2018 |
| Terna Holding AS | Real estate | 2007 |
| Terob AS | Professional & scientific | 1999 |
| Terrazzobelegg Oslo AS | Construction | 2006 |
| Terrigeno AS | Wholesale & retail | 1996 |
| Texas Reklamebyrå AS | Professional & scientific | 2015 |
| Texnes Eiendom AS | Real estate | 2011 |
| Text Query Languages AS | Information & communication | 1989 |
| Tfconsulting AS | Professional & scientific | 2022 |