| Rapid Flow Limited | Construction | 2023 |
| Rational Vaccines UK Limited | Professional & scientific | 2019 |
| Raven Carpets & Flooring Ltd | Construction | 2017 |
| RAY Mekhi's Oxford Ltd | Hospitality | 2025 |
| RCD Lockinge Ltd | Professional & scientific | 2014 |
| RD Contracting (Wantage) Limited | Agriculture & fishing | 2019 |
| RDS Commercial Limited | Professional & scientific | 2008 |
| Reable Health Ltd | Administrative & support | 2019 |
| Real Estate Marketing Corporation Ltd | Professional & scientific | 2016 |
| Realm Trading Limited | Wholesale & retail | 2021 |
| Red Seal Studio Ltd | Professional & scientific | 2023 |
| Red Skies Limited | Information & communication | 2007 |
| Redd Property Limited | Real estate | 2025 |
| Redfox Home Developments Ltd | Real estate | 2026 |
| Redwood Barn Limited | Agriculture & fishing | 2019 |
| Reed's (Wantage) Limited | Real estate | 1972 |
| Reflection Cleaning Services (Didcot) Limited | Administrative & support | 2012 |
| Regalis Property Ltd | Professional & scientific | 2020 |
| Remedy Services Limited | Other services | 2006 |
| Rencatderosayro Ltd | Professional & scientific | 2024 |
| Repair Production and Precision Engineering Limited | Manufacturing | 1972 |
| Reputation Builders PR Ltd | Professional & scientific | 2021 |
| Rescue Ventures Ltd | Extraterritorial | 2020 |
| Research Oxford Ltd | Professional & scientific | 2022 |
| REV-1 Automotive LLP | | 2023 |
| Revenue ARC Ltd | Professional & scientific | 2016 |
| Revolution Sports Therapy Limited | Health & social care | 2012 |
| Rewcastle Homes Limited | Real estate | 2023 |
| Reynard Health Supplies (UK) Limited | Health & social care | 2008 |
| RG Publishing Ltd | Information & communication | 2012 |
| Rhabdos Limited | Information & communication | 2020 |
| Richmond Parkes Ltd | Professional & scientific | 2020 |
| Ridgedale Communications Limited | Information & communication | 1999 |
| Ridgeway Challow Limited | Administrative & support | 2013 |
| Ridgeways Coaches Limited | Transport & logistics | 2006 |
| Riding for Disabled Association Abingdon Limited | Health & social care | 2011 |
| RIO Cavannagh Limited | Real estate | 2020 |
| River Property (Radcot) Limited | Real estate | 2016 |
| RJC Construction (Wantage) Ltd | Construction | 2018 |
| RJR Tree Work & Landscaping Limited | Administrative & support | 2025 |
| RJS Homes Ltd | Households | 2024 |
| Rjsw Consulting Limited | Professional & scientific | 2015 |
| Roadwise Consulting Ltd | Professional & scientific | 2025 |
| Robert Wilkinson Decorating Services Ltd | Construction | 2025 |
| Rockpool Projects Ltd | Construction | 2017 |
| Roger Claridge Violins Ltd | Manufacturing | 2012 |
| Rolling Hills Consulting Ltd | Information & communication | 2024 |
| Roomnettv Ltd | Information & communication | 2014 |
| Roper Design Ltd | Professional & scientific | 2024 |
| Rosebud Ltd | Professional & scientific | 2008 |
| Ross's Roofing Limited | Construction | 2023 |
| Rowes Group Ltd | Professional & scientific | 2025 |
| RP Structural & Co Ltd | Construction | 2023 |
| RR Morgan Ltd | Wholesale & retail | 2021 |
| Rsquare Group Ltd | Information & communication | 2025 |
| Rtmp Consultancy Ltd | Professional & scientific | 2021 |
| Run RDP Ltd | Information & communication | 2024 |
| Runor Data Consulting Ltd. | Professional & scientific | 2020 |
| Rustys Cafe Ltd | Hospitality | 2024 |
| Ryecroft South Ltd | Real estate | 2016 |
| S & S Shoe Repairs and Services Limited | Other services | 2018 |
| S Groves Property Services Ltd | Construction | 2019 |
| S-Cubed Limited | Professional & scientific | 2008 |
| S.L. White Carpentry and Joinery Ltd | Construction | 2007 |
| Safe PC Direct Ltd | Information & communication | 2018 |
| Sales Growth Expert Limited | Professional & scientific | 2016 |
| Salix Garden Services Ltd. | Administrative & support | 2022 |
| Salman Ashraf Ltd | Wholesale & retail | 2025 |
| Saltoria Marketing Ltd | Professional & scientific | 2020 |
| Same Cloth Limited | Other services | 2024 |
| Sancarios 21 Ltd | Hospitality | 2013 |
| Sanctum Oxford Limited | Construction | 2009 |
| Sandwich DE Witney Limited | Hospitality | 2002 |
| Sappy Properties (Uxbridge) LLP | | 2010 |
| SAS Groundscapes Ltd | Administrative & support | 2023 |
| Sasi Sauna Ltd | Other services | 2026 |
| Saving Energy Consultants Ltd | Professional & scientific | 2022 |
| SB General Building Services Ltd | Construction | 2015 |
| SBM Guru Limited | Extraterritorial | 2024 |
| SC Electrical Contracting (Oxford) Ltd | Construction | 2021 |
| Scatchard Surgical Ltd | Professional & scientific | 2019 |
| Scientific Computing Service Limited | Information & communication | 1938 |
| SD Plumbing (Engineering) Limited | Construction | 2016 |
| Seclo Ltd | Wholesale & retail | 2024 |
| Second Opinion Furniture Inspections and Assessments Limited | Other services | 2017 |
| Securing My Home Ltd | Administrative & support | 2010 |
| SEE Recruitment Ltd | Administrative & support | 2024 |
| Selcoms Limited | Information & communication | 2013 |
| Self Store Depot Limited | Transport & logistics | 2010 |
| Sells Family Ltd | Financial services | 2025 |
| Serica Silk Limited | Other services | 2024 |
| SERIOUS4SPORT Ltd | Education | 2023 |
| Serve Online Ltd | Wholesale & retail | 2020 |
| SET Assure Ltd | Professional & scientific | 2023 |
| SEVN21 Limited | Professional & scientific | 2020 |
| SFP Project Management Limited | Construction | 2023 |
| SH Carpentry and Construction Limited | Construction | 2014 |
| Share My PIE Ltd | Information & communication | 2026 |
| Sharif & Lambert Limited | Professional & scientific | 2022 |
| Shasidme Limited Company Ltd | Health & social care | 2018 |