| Quanttro AS | Information & communication | 2025 |
| R. Eide Invest AS | Administrative & support | 2023 |
| R.B.Auto AS | Wholesale & retail | 2011 |
| R.Jørgensen Maskin AS | Construction | 1978 |
| Raa Skogsdrift AS | Construction | 2001 |
| Radikal Dart Norge AS | Arts & recreation | 2012 |
| Ramdal Eiendomsutvikling AS | Construction | 2021 |
| Ramstein AS | Financial services | 2015 |
| Randel Consulting AS | Professional & scientific | 2020 |
| RC Smartbygg Da | Construction | 2006 |
| RDR Invest AS | Real estate | 2019 |
| Re Holding AS | Financial services | 2005 |
| Re-Com Da | Wholesale & retail | 1997 |
| Red Steel Da | Arts & recreation | 2023 |
| Redskapshagen AS | Wholesale & retail | 2024 |
| Redstag Tech AS | Information & communication | 2025 |
| Regnskapsteam Østfold AS | Professional & scientific | 2013 |
| Reklame & Folie Da | Professional & scientific | 2011 |
| Remmen Ans | Agriculture & fishing | 2009 |
| Renico AS | Wholesale & retail | 2015 |
| Repslagergata 1 AS | Real estate | 2025 |
| Respons Reklame & Folie AS | Professional & scientific | 2008 |
| Retail Deal AS | Professional & scientific | 2017 |
| Retirex AS | Water & waste | 2023 |
| Revisorteam Da | Professional & scientific | 2001 |
| Revo Invest AS | Real estate | 2013 |
| Revontulet AS | Administrative & support | 2024 |
| RGC AS | Professional & scientific | 2010 |
| Rice & Chopsticks Take Away AS | Hospitality | 2012 |
| Riis Elektro AS | Construction | 1993 |
| Rikelektro AS | Construction | 2007 |
| Ringstad Eiendom AS | Real estate | 1973 |
| Ringstad Eiendomsutvikling Ans | Real estate | 1987 |
| Ringstad Gruppen AS | Real estate | 1999 |
| Ringstad Invest AS | Real estate | 2000 |
| Ringstad Næringsutvikling AS | Real estate | 2021 |
| Riniro Invest AS | | 2025 |
| Rino Bråthen Graving Og Transport AS | Construction | 2014 |
| Rino Bråthen Graving Og Transport Da | Construction | 1992 |
| Rishaugen Eiendom AS | Real estate | 2002 |
| Riskollen AS | Real estate | 2012 |
| Risum Service AS | Construction | 2015 |
| Riva Bistro AS | Hospitality | 2020 |
| Riverside AS | Hospitality | 1994 |
| Roadstar AS | Wholesale & retail | 2024 |
| Robert Olsen AS | Wholesale & retail | 1984 |
| Robust Løsning AS | Administrative & support | 2024 |
| Rodquist Invest AS | Financial services | 2016 |
| Roger Bjerkeli Holding AS | | 2005 |
| Roger Jensen Invest AS | Real estate | 2019 |
| Roja Invest AS | Professional & scientific | 2011 |
| Rokke Barnehage SA | Education | 1989 |
| Rokke Hageservice AS | Administrative & support | 2015 |
| Rokke Va Driftsselskap SA | Water & waste | 2018 |
| Rokkeveien AS | Real estate | 2022 |
| Rolf Andreassen Og Sønner AS | Wholesale & retail | 1981 |
| Romulus Holding AS | Real estate | 2016 |
| Romulus Invest AS | Real estate | 2019 |
| Royal Eiendom AS | Real estate | 1990 |
| RRK Halden AS | Financial services | 2018 |
| Rudskogen Eiendom AS | Real estate | 2021 |
| Rudskogenveien 88 AS | Real estate | 2024 |
| Runar Consulting AS | Information & communication | 2022 |
| Rune Auensen AS | Construction | 2012 |
| Rune Brødremoen AS | Construction | 2025 |
| Rustli Arkitektur AS | Professional & scientific | 2025 |
| Rødklev AS | Financial services | 2003 |
| Rødsberget AS | Wholesale & retail | 2005 |
| Rødsberget Eiendom AS | Real estate | 2019 |
| Rødsveien 74 AS | Construction | 2007 |
| Røed Bygg & Vedlikehold AS | Construction | 2021 |
| Rørlegger Henrik Steinsvik AS | Construction | 2026 |
| Rørleggermester Henning R.Engebretsen AS | Construction | 2006 |
| Røsneskilen Vann Og Avløpslag SA | Water & waste | 2007 |
| S G Stewart Holding AS | | 2021 |
| S-T-B Eiendom AS | Real estate | 2019 |
| S.O Holding AS | Real estate | 2021 |
| S.R Sæter Eiendom AS | Real estate | 2005 |
| S16 Halden Bevaring Og Utvikling AS | Arts & recreation | 2015 |
| S88 SNR. 3 AS | Real estate | 2023 |
| S88 SNR. 5 AS | Real estate | 2023 |
| Saab Technologies Norway AS | Information & communication | 2006 |
| Saipal Invest AS | Financial services | 2005 |
| Saksæther Maskinutleie Ans | Administrative & support | 1996 |
| Sakura Sushi Take Away AS | Hospitality | 2013 |
| Salt-X AS | Wholesale & retail | 2013 |
| Samara Diskotek Ans | Hospitality | 1989 |
| Samcert AS | Education | 2019 |
| Sandbergs Holding AS | | 2025 |
| Sandbukta Bolig AS | Real estate | 2021 |
| Sanderød Eiendomsutvikling AS | Real estate | 2020 |
| Sanderød Va-Drift SA | Water & waste | 2018 |
| Sanderød Vann- Og Avløpslag SA | Water & waste | 2012 |
| Sarah Legekontor AS | Health & social care | 2013 |
| Sarchem Eiendom AS | Real estate | 1988 |
| Sarpsborg Lakkering AS | Other services | 2014 |
| Sarpsborg Lakkering AS | Other services | 2026 |
| Sarpsborg Lakkering Holding AS | | 2026 |
| Saugbrugs Bioenergi AS | Energy | 2007 |
| SB Verdi AS | Administrative & support | 2026 |