| Svestad AS | Professional & scientific | 2005 |
| Sviland BT8 S10 AS | Real estate | 2026 |
| Sviland BT8 S11 AS | Real estate | 2026 |
| Sviland BT8 S14-16 AS | Real estate | 2026 |
| Sviland BT8 S22 AS | Real estate | 2026 |
| Sviland BT8 S24 AS | Real estate | 2026 |
| Sviland BT8 S6 AS | Real estate | 2026 |
| Sviland BT8 S7 AS | Real estate | 2026 |
| Syden AS | Hospitality | 2024 |
| Sykkel-Bent Da | Wholesale & retail | 2006 |
| Symbio AS | Hospitality | 2021 |
| Systemverk AS | Wholesale & retail | 2019 |
| Syverts Invest AS | Financial services | 2011 |
| Syvertsens Gartneri AS | Agriculture & fishing | 2012 |
| Sød Acai Bowl AS | Hospitality | 2026 |
| Søm Eiendom AS | Real estate | 2021 |
| Sømsenteret Ans | | 1988 |
| Sør Gulv & Maling AS | Construction | 2016 |
| Sør Import Ans | Wholesale & retail | 2001 |
| Sør Kompetanse AS | Education | 2022 |
| Sør Trucks AS | Wholesale & retail | 2024 |
| Sørhaug Trafikkskole AS | Education | 1976 |
| Sørkonsult AS | Professional & scientific | 2022 |
| Sørlandet Fiskeguiding AS | Administrative & support | 2020 |
| Sørlandets Sykkelsenter Ans | | 1990 |
| Sørlandslisten AS | Manufacturing | 2004 |
| Sørlandslisten Da | Professional & scientific | 2004 |
| Sørlandslisten Holding AS | Manufacturing | 2011 |
| Sørskjell AS | Agriculture & fishing | 2016 |
| Sørvestor AS | | 2025 |
| Sørvåg Entreprenør AS | Construction | 2010 |
| Sørvåg VVS AS | Construction | 2020 |
| Søstrene På Låven AS | Manufacturing | 2010 |
| T Skalleberg Holding AS | | 2021 |
| T W Wilson Eiendom AS | Construction | 2005 |
| T-Utleie AS | Administrative & support | 2024 |
| T. Aas Invest AS | Real estate | 2005 |
| Tangen Allé 2 AS | Real estate | 2024 |
| Tangenheia AS | Real estate | 2012 |
| Tannlege Heen AS | Health & social care | 2013 |
| Tannlege Lars Jomås AS | Health & social care | 2007 |
| Tatech AS | Manufacturing | 2008 |
| TCG South AS | Wholesale & retail | 2025 |
| Team Bygg Norge AS | Construction | 2022 |
| Team Kringeland Eriksen AS | Agriculture & fishing | 2024 |
| Techstad AS | Professional & scientific | 2025 |
| Tek AS | Real estate | 2014 |
| Teknologiveien 3 AS | Real estate | 2020 |
| Telman AS | Information & communication | 2022 |
| Temse Invest AS | | 2026 |
| Temseveien Barnehage AS | Education | 2006 |
| Terje Løvås Vei 1 AS | Real estate | 1996 |
| Terramarine AS | Manufacturing | 2020 |
| TH Brenni & Co Ltd AS | Wholesale & retail | 1931 |
| The House of Cognac AS | Wholesale & retail | 1998 |
| The Snafu Company AS | Information & communication | 2025 |
| Therkildsen Holding AS | | 2023 |
| Thorsen & Braves AS | Information & communication | 2022 |
| THT AS | Real estate | 2023 |
| Thunestvedt Elektriske AS | Construction | 1994 |
| Thurinus Holding AS | Professional & scientific | 2015 |
| Thygesen Eiendom AS | Real estate | 2021 |
| Ti Tjenester AS | Administrative & support | 2023 |
| Tickify AS | Information & communication | 2012 |
| Tina Elstad Holding AS | Hospitality | 2022 |
| Tingsted AS | Information & communication | 2023 |
| Tingvold Ventures AS | | 2023 |
| Tirafondo AS | Wholesale & retail | 2019 |
| Tiril AS | Arts & recreation | 2018 |
| Tjemsland & Møller AS | Professional & scientific | 2005 |
| Tjuesju AS | | 2021 |
| TL Drift AS | Manufacturing | 2021 |
| TL Montasje AS | Construction | 2021 |
| TMH Blikkenslager AS | Construction | 2015 |
| TMT Invest AS | Construction | 2019 |
| Tomas B Snekring Og Maling AS | Construction | 2015 |
| Tomstad AS | Professional & scientific | 2012 |
| Tonje P Holding AS | Wholesale & retail | 2022 |
| Toolmakers AS | Construction | 2022 |
| Toppen Invest AS | | 2001 |
| Tordens AS | Real estate | 2010 |
| Tore Stalleland AS | Professional & scientific | 2015 |
| Tore Wickstrøm Holding AS | Financial services | 2015 |
| Torskeholmen Ans | Real estate | 1991 |
| Torskeholmen AS | Real estate | 2018 |
| Torunn Anthonsen Healing AS | Health & social care | 2023 |
| Torvet 1B AS | Real estate | 2025 |
| Tovhei Eiendom AS | | 2013 |
| TR Båt & Fritid AS | Wholesale & retail | 2015 |
| Transparent Mind AS | Information & communication | 2025 |
| Travel Cue Management AS | Administrative & support | 2024 |
| Tre Mestere Holding AS | Construction | 2019 |
| Tre-Mestere AS | Construction | 2019 |
| Trenco Eiendom AS | Health & social care | 1998 |
| Trippelr AS | Other services | 2022 |
| Triton AS | Real estate | 2012 |
| Troliai Uab | Construction | 2006 |
| Trolldalstoppen Tomteutvikling AS | Real estate | 2018 |
| Trommestad Holding AS | | 2022 |
| Trygun AS | | 2024 |