| Old Station Nannies Limited | Education | 2020 |
| Olive Wealth Management Limited | Financial services | 2008 |
| Orange & Bear Limited | Wholesale & retail | 2025 |
| Orchard House Associates Ltd | Professional & scientific | 2025 |
| Orchard Paddock Residents Limited | Households | 1986 |
| OX and Hart Financial Services Ltd | Financial services | 2021 |
| Oxford House Faringdon Ltd | Real estate | 2024 |
| Oxford Human Capital Incorporated Ltd | Agriculture & fishing | 2020 |
| Oxford Review Enterprises Ltd | Information & communication | 2018 |
| Oxford Roofing and Maintenance Ltd | Construction | 2020 |
| Oxfordshire Counselling and Psychology Practice Ltd | Health & social care | 2014 |
| Oxlot.Co.Uk Ltd | Professional & scientific | 2001 |
| Oxslot Limited | Agriculture & fishing | 2001 |
| P J Freeman Electrical Ltd | Construction | 2018 |
| P.F.S. Properties Limited | Real estate | 2000 |
| Paltron Ltd | Real estate | 2019 |
| Panlegal Limited | Professional & scientific | 2006 |
| Passeri Limited | Professional & scientific | 2021 |
| PAT Thomas (Faringdon) Limited | Real estate | 1962 |
| Paul Gough Transport Ltd | Transport & logistics | 2019 |
| Peacock Property Solutions Ltd | Construction | 2018 |
| Pear Tree Hospitality Limited | Professional & scientific | 2023 |
| Pecwom Autocentre Ltd | Wholesale & retail | 2025 |
| Pepler Fine Fencing Limited | Construction | 2005 |
| Perks Pumping Services Ltd | Construction | 2019 |
| Petroleum Integrity Solutions Limited | Professional & scientific | 2012 |
| Pheladi Ltd | Health & social care | 2014 |
| Phil Benson Contracting Ltd. | Agriculture & fishing | 2009 |
| Photomec (London) Limited | Manufacturing | 1946 |
| Piano Gallery Ltd | Wholesale & retail | 2012 |
| Pick 'N' MIX Music Ltd | Extraterritorial | 2015 |
| Picture Perfect Gardens Ltd | Administrative & support | 2019 |
| Pilates Playroom Limited | Other services | 2019 |
| Pink Pigeon Production Music Ltd | Information & communication | 2025 |
| Pink Pigeons Trust | Arts & recreation | 2010 |
| Pioneer Autos Limited | Wholesale & retail | 2010 |
| Piranha Logistics Group Ltd | Financial services | 2016 |
| Piranha Paintwork & Body Repairs Ltd | Wholesale & retail | 2021 |
| Piranha Tyre Solutions Ltd | Wholesale & retail | 2024 |
| Pirineus Consulting Limited | Administrative & support | 2019 |
| Placement Professionals Ltd | Administrative & support | 2025 |
| Placeway Limited | Real estate | 1999 |
| Planning Change Ltd | Professional & scientific | 2011 |
| Platinum Security Services Limited | Administrative & support | 2020 |
| PMG Retail Limited | Wholesale & retail | 2004 |
| Polaris QA Consultants Limited | Professional & scientific | 2014 |
| Polkadot Day Nurseries Limited | Education | 2004 |
| Poppies Landscapes Limited | Administrative & support | 2023 |
| Portwell Angel Services Ltd | Administrative & support | 2009 |
| Power Bloodstock Limited | Arts & recreation | 2011 |
| Powt Challow (Management) Limited | Households | 2023 |
| Precision Grounds Care Ltd | Administrative & support | 2025 |
| Precision QA Limited | Professional & scientific | 2023 |
| Premier Nurseries Limited | Education | 1991 |
| Prestige Vehicle Leasing Ltd | Administrative & support | 2026 |
| Pretty Vintage Boutique Limited | Wholesale & retail | 2020 |
| Printable Parties Limited | Professional & scientific | 2023 |
| Priority Manufacturing Ltd | Manufacturing | 2024 |
| Pro Tiling Design Ltd | Construction | 2018 |
| Pro's Holdings Limited | Financial services | 2021 |
| Property Happiness Ltd | Construction | 2024 |
| Propertyknowhow Limited | Real estate | 2016 |
| Prospectedge Ltd | Professional & scientific | 2025 |
| Pulham & Co. Group Ltd | Professional & scientific | 2025 |
| Pusey Furze Barns Management Company Limited | Real estate | 2010 |
| PVN Ltd | Information & communication | 2019 |
| Pyxis Program Management Ltd | Professional & scientific | 2019 |
| Qict Limited | Wholesale & retail | 2005 |
| Qualisure Consulting Ltd | Information & communication | 2025 |
| Quantumed BIO Limited | Wholesale & retail | 2022 |
| R & D Mcbain (Contractors) Limited | Construction | 1974 |
| R & S Construction (UK) Limited | Construction | 2002 |
| R Capper Limited | Construction | 2010 |
| R M Wetlands & Environment Ltd | Professional & scientific | 2011 |
| Radcliffe Enterprise Law Ltd | Professional & scientific | 2026 |
| Radcliffe Enterprise Solicitors Limited | Professional & scientific | 2026 |
| Radcot Groundworks Limited | Construction | 2005 |
| Radiation Metrology Limited | Professional & scientific | 2014 |
| Radnor Court Management Company Limited | Households | 2020 |
| Ragnell Barns Management Company Limited | Households | 2019 |
| Readidance Community Interest Company | Education | 2019 |
| Red Design Ergonomics Limited | Professional & scientific | 2010 |
| Red Dragon Carpentry Ltd | Construction | 2025 |
| Rejuvenate Property Services Ltd | Construction | 2023 |
| Renewing YOU Ltd | Other services | 2025 |
| Residents of Treadwells Management Ltd | Extraterritorial | 2012 |
| Reward-First People Consulting Limited | Professional & scientific | 2004 |
| Rhianfa Limited | Hospitality | 1991 |
| Rhubarb Shop Ltd | Wholesale & retail | 2024 |
| Ridgeway Aerotech Ltd | Professional & scientific | 2022 |
| Ridgeway Drive Management Company Limited | Households | 2014 |
| Riko LOG Consult Limited | Transport & logistics | 2016 |
| Riverside Hotel Kendal Limited | Hospitality | 2004 |
| Rlni Computers Limited | Information & communication | 2020 |
| Robert Todd Limited | Manufacturing | 2010 |
| Romney Residents Management Company Limited | Real estate | 1990 |
| Rose Racing Limited | Professional & scientific | 2025 |
| Rosey Property Limited | Real estate | 2025 |
| Ross Properties (Aldene) Ltd | Construction | 2016 |
| Ross Properties [ LEA ] Ltd | Real estate | 2023 |