| Pyramid Learning (Europe) Limited | Education | 2020 |
| Pyrra Technologies Ltd | Information & communication | 2025 |
| Q Element Ltd | Professional & scientific | 2017 |
| Q Transport (Oxford) Limited | Transport & logistics | 2003 |
| Q&L-Ostech Limited | Information & communication | 2017 |
| Q.S Group Ltd | Wholesale & retail | 2015 |
| Qanata Labs Limited | Information & communication | 2025 |
| Qarachatan Limited | Other services | 2024 |
| Qazi Properties Limited | Real estate | 2020 |
| QBD Group Ltd | Professional & scientific | 2009 |
| QIN Noodle Ltd | Hospitality | 2024 |
| QIO JEN Ltd | Real estate | 2024 |
| QL Coffee House Limited | Hospitality | 2003 |
| QMQ Limited | Wholesale & retail | 2022 |
| QQM Ltd | Administrative & support | 2010 |
| Qrkr Ltd | Administrative & support | 2024 |
| Qsoft Infotech Limited | Information & communication | 2025 |
| Quad Limited | Construction | 2006 |
| Quadview Limited | Households | 1991 |
| Quadview MARK2 Limited | Households | 2004 |
| Quaere Ltd | Professional & scientific | 2018 |
| Quainton Garage LLP | | 2019 |
| Qualitation Ltd | Professional & scientific | 2015 |
| Quality Business & Educational Services Limited | Manufacturing | 1957 |
| Quantic Capability Solutions Limited | Professional & scientific | 2005 |
| Quantic Management Solutions Limited | Professional & scientific | 2005 |
| Quantro Support Limited | Administrative & support | 2024 |
| Quantrolox Limited | Information & communication | 2021 |
| Quantum Brain Art Limited | Professional & scientific | 2019 |
| Quantum Corporate Coaching Limited | Professional & scientific | 2008 |
| Quantum Dice Limited | Manufacturing | 2020 |
| Quarn Investments Ltd | Real estate | 2025 |
| Quarry Developments Oxford Limited | Construction | 2017 |
| Quarry Medical Consultancy Ltd | Health & social care | 2018 |
| Quarry Mews Limited | Construction | 2018 |
| Quasar Medical Limited | Health & social care | 2023 |
| Quds Properties Ltd | Real estate | 2025 |
| Queen of Parts Ltd | Wholesale & retail | 2025 |
| Queensgate Freehold Limited | Households | 2021 |
| Querca TOO - Medical & Scientific Communications Ltd | Professional & scientific | 2024 |
| Quiane Consulting LLP | | 2011 |
| Quickbuyown Ltd | Wholesale & retail | 2025 |
| Quickgo Ltd | Transport & logistics | 2025 |
| Quirky Barber Ltd | Other services | 2022 |
| Quod Electrical Ltd | Construction | 2012 |
| Quotez Ltd | Information & communication | 2024 |
| Quotidian Strategies Ltd | Professional & scientific | 2021 |
| Quotus Limited | Information & communication | 2012 |
| Qylm &New Life Ltd | Hospitality | 2024 |
| QZ Oxford Limited | Hospitality | 2023 |
| R & a Seal Ltd | Construction | 2011 |
| R & C Bros. Ltd | Health & social care | 2022 |
| R & D Nobes Brickwork Limited | Construction | 2015 |
| R & W Associates UK Limited | Information & communication | 1994 |
| R and G Building Services (Oxford) Ltd | Construction | 2011 |
| R and J Broomfield Construction Limited | Construction | 2024 |
| R and Lata Brothers Ltd | Hospitality | 2025 |
| R C M G Oxford Ltd | Agriculture & fishing | 2011 |
| R G & H N Benson Ltd | Agriculture & fishing | 2020 |
| R Griffiths Woodwear Limited | Manufacturing | 1974 |
| R Hamlet Limited | Construction | 2001 |
| R M Couriers Limited | Transport & logistics | 2003 |
| R N Roofing Specialists Limited | Construction | 2026 |
| R V Arts Limited | Transport & logistics | 2012 |
| R V Haulage Ltd | Transport & logistics | 2018 |
| R&M Building Works Ltd | Construction | 2019 |
| R&M Diamonds Ltd | Manufacturing | 2025 |
| R&M Geoscience Ltd | Professional & scientific | 2026 |
| R&S Property Maintenance Services Ltd | Construction | 2023 |
| R&S Property Oxford Limited | Real estate | 2024 |
| R. J. Harrison Plumbing & Heating Limited | Construction | 2003 |
| R.B.S Hampshire Limited | Real estate | 2018 |
| R.B.S. Sunrise Limited | Real estate | 2023 |
| R.Hayward | | 1971 |
| R.J. & S. Styles Limited | Construction | 1973 |
| R.M.A. Properties Limited | Real estate | 1995 |
| R.S. Vehicle Performance Consultancy Limited | Other services | 2019 |
| R.S.M. Joinery Limited | | 1975 |
| R.T.E.M Ltd | Manufacturing | 2006 |
| R.T.H. Holdings Limited | Financial services | 2017 |
| R2GO Couriers Ltd | Transport & logistics | 2026 |
| R4PID Operations Ltd | Professional & scientific | 2020 |
| R4PID UK Ltd | Wholesale & retail | 2024 |
| RA & Associates Limited | Professional & scientific | 2000 |
| RA OXF Properties Limited | Real estate | 2025 |
| Rabi Farmers Trading Ltd | Other services | 2025 |
| RABR88 Ltd | Wholesale & retail | 2025 |
| Race Air Dynamics Ltd | Manufacturing | 2024 |
| Rachel Makari Limited | Professional & scientific | 2016 |
| Rachel Ryan Tutoring Ltd | Education | 2025 |
| Rachu Limited | Professional & scientific | 2022 |
| Racz 24/7 Limited | Construction | 2022 |
| Radcliffe Academy Trust | Education | 2014 |
| Radcliffe Watches Limited | Manufacturing | 2021 |
| Radiance Defined Aesthetics Ltd | Health & social care | 2026 |
| Radius Intelligent Automation Ltd | Information & communication | 2020 |
| Radix 2 Limited | Information & communication | 2006 |
| Radix 2 Technologies Ltd | Professional & scientific | 2017 |
| Radley Court (Kennet Road) Management Limited | Households | 1999 |
| Radley Wood Court Management Limited | Households | 1998 |