| Sunbelt Bedriftsmegling AS | Professional & scientific | 2005 |
| Sunnlandsvegen 4 AS | Real estate | 2021 |
| Sustainable AS | | 2020 |
| Sustevo AS | Professional & scientific | 2016 |
| Svalastog Cloud AS | Information & communication | 2023 |
| Svendsen Prosjektutvikling AS | Real estate | 1987 |
| Sverre Kragstad AS | Wholesale & retail | 1998 |
| Sympower Norway AS | Information & communication | 2023 |
| Söderberg & Partners Affinity AS | | 2025 |
| Söderberg & Partners AS | Financial services | 1992 |
| Söderberg & Partners Distribusjon AS | Financial services | 2004 |
| Söderberg & Partners Medlemsforsikring AS | Financial services | 1994 |
| T-H Holding AS | | 2020 |
| T-Park Halden AS | Transport & logistics | 2005 |
| T.O.Olsen AS | | 2020 |
| Tag Bygg Partner AS | Construction | 2024 |
| Tag Group AS | Construction | 2021 |
| Taksrud AS | Information & communication | 2021 |
| Talent.As AS | Arts & recreation | 1993 |
| Tallyman AS | Transport & logistics | 2007 |
| Tamigo Norge AS | Wholesale & retail | 2004 |
| Tank Management AS | Transport & logistics | 2006 |
| Tanke Svilandsgate 73 AS | Real estate | 2004 |
| Tannlegeverket Fornebu AS | Health & social care | 2021 |
| Tapad Norway AS | Information & communication | 2016 |
| Taraldsen Group AS | | 2021 |
| Taraldsen Property AS | Real estate | 2025 |
| Target Wines AS | Wholesale & retail | 2014 |
| Taterholmen AS | Real estate | 2023 |
| Tavler AS | Information & communication | 2020 |
| Taxi 02000 AS | Transport & logistics | 2007 |
| Taxisentralen 02000 AS | Transport & logistics | 2004 |
| TBW Holding AS | | 2024 |
| TEAM2ME AS | Information & communication | 2013 |
| Tebe Invest AS | | 2021 |
| Techem Norge AS | Wholesale & retail | 2008 |
| Technip Canada Ltd | Mining & quarrying | 2006 |
| Technip Coflexip Norge AS | Mining & quarrying | 2000 |
| Technip Geoproduction (M) Sdn.Bhd. | Administrative & support | 2012 |
| Technip USA Inc | Professional & scientific | 2010 |
| Technipfmc UK Limited | Mining & quarrying | 1995 |
| Techpoint Norge AS | Wholesale & retail | 2025 |
| Techtronic Industries Norway AS | Wholesale & retail | 2004 |
| Teco Holding AS | Wholesale & retail | 2005 |
| Teknotherm Marine AS | Wholesale & retail | 2011 |
| Telecom Equity Partner (Mauritius) Ltd | | 2011 |
| Telecom Management Partner AS | Information & communication | 2010 |
| Telemar-Tnl Holding AS | | 2025 |
| Teleplan AS | Information & communication | 1993 |
| Teleplan Consulting AS | Information & communication | 1998 |
| Teleplan Eiendom AS | Real estate | 2012 |
| Teleplan Eiendom Fritid AS | Real estate | 2023 |
| Teleplan Globe AS | Information & communication | 1973 |
| Teleplan Holding AS | Information & communication | 1957 |
| Telinet Energi Holding AS | Energy | 2022 |
| Telinet Invest AS | Energy | 2003 |
| Tellu AS | Information & communication | 2016 |
| Tengberg Konsult AS | Professional & scientific | 2022 |
| Ternos AS | | 2024 |
| Terra Miljø AS | Professional & scientific | 2024 |
| Tesfu Holding AS | | 2016 |
| Tetra Pak Norge AS | Wholesale & retail | 1958 |
| Tewa AS | Wholesale & retail | 2019 |
| The British School of Oslo AS | Education | 2023 |
| The Concept AS | Wholesale & retail | 2023 |
| The Qrill Company Holding AS | Agriculture & fishing | 2024 |
| The Qrill Company Services AS | Administrative & support | 2013 |
| The Resource Group TRG AS | Agriculture & fishing | 2000 |
| The Shade AS | Wholesale & retail | 2022 |
| The Studio Fitness & Lifestyle AS | Arts & recreation | 2007 |
| Thor Halvorsen Holding AS | Hospitality | 2005 |
| THV. Meyersgt. 51 AS | Real estate | 1999 |
| Tikal AS | Financial services | 2004 |
| Tinholt Gruppen AS | Real estate | 2014 |
| Tinson AS | Hospitality | 2009 |
| Titlestad & Hauger AS | Professional & scientific | 1964 |
| Titlis AS | Real estate | 1997 |
| Titus Invest AS | | 2021 |
| Tjenestetorget AS | Information & communication | 1997 |
| Tjenestetorget Finans AS | Financial services | 2019 |
| TJP Medical AS | Health & social care | 2025 |
| TJV AS | Real estate | 2022 |
| TKV Invest AS | Manufacturing | 2008 |
| Tobla AS | Financial services | 2008 |
| Toluma AS | Financial services | 1947 |
| Toluma Global AS | Financial services | 1999 |
| Toluma Invest AS | Real estate | 2000 |
| Toluma Kreditt AS | Financial services | 2012 |
| Toluma Norden AS | Financial services | 2001 |
| Toluma Regnskap AS | Professional & scientific | 2001 |
| Tomaco AS | Professional & scientific | 2017 |
| Tonor Næring AS | Real estate | 2007 |
| Top Cellars Wine Import AS | Wholesale & retail | 2016 |
| Topaas Og Haug Entreprenør AS | Construction | 2026 |
| Topeka Holding AS | Transport & logistics | 2019 |
| Topeka MPC Maritime AS | | 2022 |
| Tordenskioldsgate 6B AS | Real estate | 2020 |
| Torsvik Invest AS | Information & communication | 2013 |
| Toruk AS | Information & communication | 2015 |
| Tradedoubler AS | Information & communication | 2000 |