| Vip Trafikkskole AS | Education | 2017 |
| Visoni AS | Professional & scientific | 2019 |
| Visuell AS | Wholesale & retail | 2013 |
| Vital Skin Care AS | Health & social care | 2021 |
| Vitale Regnskap AS | Professional & scientific | 2025 |
| Viva Cruises AS | Administrative & support | 2025 |
| Vixxion AS | | 2025 |
| VML Map Norway Nuf | Professional & scientific | 2013 |
| VRS Renholdssystemer AS | Administrative & support | 2013 |
| VVS Entreprenøren AS | Construction | 2024 |
| VVS Tjenesten AS | Construction | 2019 |
| VXL Pro Renhold Og Maleri AS | Administrative & support | 2026 |
| Walker & Walker Bryllupssalong Ans | Administrative & support | 1990 |
| Wallentin AS | Professional & scientific | 2015 |
| Wangberg Eiendom AS | Real estate | 2006 |
| Wangberg Holding AS | Administrative & support | 2016 |
| Waso AS | Professional & scientific | 2026 |
| Webbynavia AS | Information & communication | 2021 |
| Weberg Auto AS | Wholesale & retail | 2022 |
| West Pipe AS | Construction | 2011 |
| Westvang Eiendom Ans | Real estate | 2012 |
| Westwood Studios AS | Professional & scientific | 2026 |
| Wiax Eiendomstjenester AS | Administrative & support | 2026 |
| Wibe Capital AS | | 2026 |
| Wig Wam AS | Arts & recreation | 2020 |
| Wiig Performance AS | Other services | 2021 |
| Wilbergjordet Barnehage AS | Education | 2022 |
| Witek AS | Real estate | 2014 |
| Witnes Eiendom AS | Real estate | 2011 |
| Witnes Forvaltning AS | Real estate | 2024 |
| Witnes Holding AS | Real estate | 2012 |
| Wooly Wonder AS | Wholesale & retail | 2023 |
| Xo Beauty & Academy AS | Other services | 2024 |
| Yoba AS | Education | 2023 |
| Yoke AS | Health & social care | 2020 |
| Zak Holding AS | | 2025 |
| Zenith Survey AS | Professional & scientific | 2013 |
| Zenobeauty AS | Other services | 2025 |
| Zo Holding AS | Education | 2013 |
| Zystm AS | Professional & scientific | 2009 |
| Ådalen Eiendom AS | Real estate | 2012 |
| Ådalen Invest AS | Wholesale & retail | 2011 |
| Åkebergmosen 6 AS | Real estate | 2021 |
| Øa Drift AS | Administrative & support | 2021 |
| Øbs Holding AS | | 2026 |
| Ødegaard Distribusjon Ans | Transport & logistics | 2004 |
| Økernly Barnehage AS | Education | 2022 |
| Ørseng Interiørarkitektur AS | Professional & scientific | 2019 |
| Ørseng Vann- Og Avløpslag SA | Construction | 2023 |
| Øst Inspeksjon AS | Manufacturing | 2011 |
| Østfold Betongsaging AS | Construction | 2026 |
| Østfold Bilutleie AS | Administrative & support | 2007 |
| Østfold Bolig Da | Construction | 2009 |
| Østfold Boligservice AS | Administrative & support | 2014 |
| Østfold Bruktbil AS | Wholesale & retail | 2020 |
| Østfold Burger AS | Hospitality | 2023 |
| Østfold Byggconsult AS | Construction | 2013 |
| Østfold Dagligvarer 1 AS | Wholesale & retail | 2023 |
| Østfold Fasadevask AS | Real estate | 2016 |
| Østfold Forsikring AS | Financial services | 2013 |
| Østfold Forsikringssenter AS | Real estate | 2014 |
| Østfold Golfsenter AS | Arts & recreation | 2000 |
| Østfold Indremedisin AS | Health & social care | 2007 |
| Østfold Klinikken AS | Health & social care | 2006 |
| Østfold Kornmagasin AS | Transport & logistics | 2018 |
| Østfold Logopedtjeneste AS | Health & social care | 1995 |
| Østfold Pizza Lande AS | Hospitality | 2011 |
| Østfold Ren Kvalitet AS | Administrative & support | 2025 |
| Østfold Rengjøring AS | Administrative & support | 2022 |
| Østfoldhus AS | Real estate | 1971 |
| Østlandsk Karosseri AS | Other services | 2003 |
| Øyelege J.R. Ekstrand AS | Health & social care | 2006 |
| Øystein Trippestad AS | Wholesale & retail | 2020 |
| Østfold Returpapir AS | Manufacturing | 1975 |