| Spydeberg Kulturstasjon AS | Administrative & support | 2021 |
| Spydeberg Miljødeponi AS | Mining & quarrying | 2012 |
| Spydeberg Næringspark AS | Real estate | 2013 |
| Spydeberg Radio Og TV Ans | Wholesale & retail | 2008 |
| Spydeberg Regnskapslag SA | Professional & scientific | 1952 |
| Spydeberg Reklame AS | Professional & scientific | 2012 |
| Spydeberg Rock AS | Arts & recreation | 2012 |
| Spydeberg Treningssenter AS | Arts & recreation | 2012 |
| Spydeberg Utemiljø AS | Administrative & support | 2010 |
| Spydeberg Yrkes & Fritidsklær AS | Wholesale & retail | 2015 |
| Spydebergveien Holding AS | Real estate | 2025 |
| Spyleservice Østfold AS | Water & waste | 2024 |
| Starpoint AS | | 2026 |
| Staselig AS | Administrative & support | 2026 |
| Stasjonsdrift Haals Wennevold AS | Wholesale & retail | 2020 |
| Stasjonsgata 38 AS | Real estate | 2021 |
| Stavrex AS | Wholesale & retail | 2018 |
| Steel Construction Bulajic AS | Manufacturing | 2021 |
| Stein Og Jord Deponi AS | Construction | 2006 |
| Steinar Kvisler AS | Construction | 2003 |
| Stine Marie Møllerop Holding AS | Financial services | 2014 |
| Storaborg Eiendom AS | Real estate | 2007 |
| Strøms Holding Invest AS | Real estate | 2008 |
| Stuss Frisør AS | Other services | 2023 |
| Superolsen AS | | 2022 |
| Svarstad AS | Professional & scientific | 2000 |
| Svenneby Sag Og Høvleri AS | Manufacturing | 2009 |
| Syni AS | Real estate | 2014 |
| Sørlie Eiendomsutvikling AS | Real estate | 2025 |
| Sørlie Pukk AS | Mining & quarrying | 2021 |
| Sørlie Transport AS | Transport & logistics | 2012 |
| Tab Eiendomsinvest AS | Construction | 2023 |
| Tannlege K. Ruud AS | Health & social care | 2026 |
| Tannlege Kaja Egeland Brettingen AS | Health & social care | 2012 |
| Tannlege Kari Ruud AS | Real estate | 2026 |
| Tannlege Suslu AS | Health & social care | 2020 |
| Team Bygg Og Anlegg AS | Construction | 2016 |
| Tenebris Eiendom AS | | 2026 |
| THB Investeringer AS | | 2020 |
| The Bogens Invest AS | | 2025 |
| The Norwegian Dream AS | Information & communication | 2021 |
| Theoliv AS | Wholesale & retail | 2024 |
| Thimes Holding AS | Real estate | 2023 |
| Thomas Oraug Invest AS | Real estate | 2017 |
| TL Bolig AS | Construction | 2018 |
| TM Løken Eiendom AS | Real estate | 2007 |
| TN Varmeteknikk AS | Construction | 2017 |
| Tn-Gruppen AS | Construction | 2018 |
| To Fulle Menn AS | Professional & scientific | 2017 |
| Tom Fredrich Hetland-Lysne AS | Wholesale & retail | 2020 |
| Tomt Og Landskapsutvikling AS | Construction | 2005 |
| Tomter Park 2 AS | Real estate | 2021 |
| Tomter Park AS | Real estate | 2021 |
| Total Web Da | Information & communication | 2000 |
| Trattoria Galtebo AS | Hospitality | 2019 |
| Trekanten AS | Real estate | 1981 |
| Trekanten Konditori Da | Hospitality | 1997 |
| Trelleborg Holding Norge AS | Wholesale & retail | 1987 |
| Trelleborg Pipe Seals Lelystad B.V. | Wholesale & retail | 2002 |
| Trelleborg Pipe Seals Spydeberg AS | Wholesale & retail | 1981 |
| Trndz AS | Information & communication | 2015 |
| Trond T. Wikant AS | Wholesale & retail | 2020 |
| Tronstadveien 2 AS | Real estate | 2014 |
| Tryll AS | Information & communication | 2017 |
| Trøkk AS | Arts & recreation | 2005 |
| TS Tømrerservice AS | Construction | 2018 |
| Tunby AS | Manufacturing | 1964 |
| Tunby Holding AS | Real estate | 1992 |
| Tunveien AS | | 2014 |
| Tutunest AS | Wholesale & retail | 2023 |
| Tyttebæret Barnehage SA | Education | 2002 |
| Tømrermester Thor Arne Bjerke AS | Construction | 2012 |
| Ubud AS | | 2024 |
| Ullvogna AS | Wholesale & retail | 2015 |
| Undervannsteknikk.No AS | Professional & scientific | 2022 |
| Unnerud Vestre AS | | 2009 |
| Utilia AS | Manufacturing | 2024 |
| V.K Holding AS | | 2026 |
| Vartdal Plast Øst Og Midt AS | Manufacturing | 2024 |
| Vatn Energi AS | Energy | 2012 |
| VB Hus AS | Construction | 2019 |
| Velandmedia AS | Arts & recreation | 2022 |
| Velvet Recording AS | Arts & recreation | 2014 |
| Ventilasjonsservice AS | Construction | 2019 |
| Veros AS | Wholesale & retail | 2026 |
| Vestby Tower AS | Construction | 2022 |
| Vien Compagniet AS | Wholesale & retail | 2012 |
| Viken Solskjerming AS | Construction | 2018 |
| Villaveien Legesenter Da | Health & social care | 2005 |
| Vister Invest AS | | 2021 |
| Vister Prestby Da | Agriculture & fishing | 2024 |
| Vollene Investering AS | Real estate | 2005 |
| VSR Holding AS | Professional & scientific | 2010 |
| VTF Eiendom AS | Real estate | 2022 |
| VVS Comfort AS | Construction | 1970 |
| Vøyen Arena AS | Administrative & support | 2023 |
| Westby Eiendom AS | Real estate | 2005 |
| Westby Gruppen AS | Information & communication | 2005 |
| Woodworks AS | Construction | 2022 |
| Åryd Invest AS | Professional & scientific | 2012 |