| Orrock Admin Limited | Other services | 2024 |
| Osborn Consultancy Ltd | Professional & scientific | 2019 |
| Osborne Heath Estate Agents Limited | Real estate | 2016 |
| Osullivan Formwork Limited | Construction | 2008 |
| Otis Batterbee Limited | Wholesale & retail | 2011 |
| OTT Mechanical Services Limited | Wholesale & retail | 2025 |
| OUR Care Network Ltd | Health & social care | 2024 |
| Outer Reality Ltd | Information & communication | 2023 |
| Over the Moon Childcare Ltd | Health & social care | 2025 |
| OX Support Services Limited | Professional & scientific | 2017 |
| Oxford HR (Group) Ltd | Administrative & support | 2011 |
| Oxford Human Resource Consultants Limited | Administrative & support | 2007 |
| Oxford Partnership for Education Research and Analysis LLP | | 2017 |
| Oxford Sound Equipment Limited | Information & communication | 2015 |
| Oxford Sound Mixing Limited | Information & communication | 2015 |
| Oyster Projects Limited | Construction | 2001 |
| OZER4912 Limited | Other services | 2025 |
| P Arie Trading Limited | Hospitality | 2017 |
| P&B Ascot Limited | Hospitality | 2022 |
| P. P. Enhancements Limited | Manufacturing | 2015 |
| Paceplay Ltd | Information & communication | 2025 |
| Painless Limited | Professional & scientific | 2005 |
| Paletan Limited | Information & communication | 2023 |
| Pallicons Limited | Administrative & support | 2018 |
| Pallison Consulting Limited | Administrative & support | 2013 |
| Palm Equity Partners Ltd | Professional & scientific | 2026 |
| Palma Ceia Semidesign (UK) Limited | Information & communication | 2019 |
| Pantaleo Productions Ltd | Manufacturing | 2022 |
| Pantheon Consultancy Limited | Professional & scientific | 2018 |
| Panurgy Ltd | Professional & scientific | 2022 |
| Papillon Speakers Limited | Arts & recreation | 2021 |
| Papplewick Educational Trust Limited | Education | 1964 |
| Paradise Eco Homes Ltd | Wholesale & retail | 2012 |
| Paradise Shutters Limited | Construction | 2023 |
| Paradon Properties Limited | Construction | 2013 |
| Paragon Executive Search Ltd | Professional & scientific | 2010 |
| Paris Nails Limited | Other services | 2023 |
| Park Villas (UK) Limited | Other services | 2007 |
| Parlour Group Limited | Real estate | 2021 |
| Parmar Property Enterprise Ltd | Real estate | 2021 |
| Parmar Property Investments Ltd | Real estate | 2016 |
| Paruk & Co Ltd | Information & communication | 2025 |
| Pasapas UK Limited | Information & communication | 2011 |
| Patel & Sons Property Investments Ltd | Real estate | 2021 |
| Pateria Limited | Administrative & support | 1998 |
| Paul Berman Consulting Limited | Other services | 2017 |
| Paul Janman Limited | Wholesale & retail | 2005 |
| Paul Vidgen Forest Machines Limited | Wholesale & retail | 2013 |
| Pavilion Makes Ltd | Manufacturing | 2026 |
| Pawar 8 Ltd | Professional & scientific | 2024 |
| Pawar Performance Limited | Professional & scientific | 2025 |
| Paxos Technology Limited | Financial services | 2016 |
| Pbld Limited | Professional & scientific | 2007 |
| Pcma UK Management & Productions Ltd | Information & communication | 2021 |
| PCO Consultancy Ltd | Professional & scientific | 2020 |
| PD Management Services Limited | Professional & scientific | 2024 |
| Peak 15 Media Ltd | Information & communication | 2017 |
| Peal Management Holdings Limited | Professional & scientific | 2009 |
| Pembroke Mews Sunninghill Limited | Households | 1998 |
| Peninvest Limited | Professional & scientific | 2004 |
| Penny Illston Ltd | Professional & scientific | 2018 |
| Pentagon Clinic LLP | | 2015 |
| People Work Life Limited | Professional & scientific | 2025 |
| Permacoat Resin & Paving Ltd | Construction | 2023 |
| Permasteelisa Collateral Management Limited | Financial services | 1984 |
| Perspective Device Consulting Limited | Professional & scientific | 2014 |
| Petrenel Limited | Professional & scientific | 2016 |
| Phantom IT Limited | Information & communication | 2022 |
| Pharos Advisory Ltd | Professional & scientific | 2026 |
| Phase Two Design Limited | Professional & scientific | 2020 |
| Phil Hanson Endurance Racing Limited | Arts & recreation | 2017 |
| Phil Hanson Racing Limited | Arts & recreation | 2017 |
| Phil Wills Associates Limited | Administrative & support | 2009 |
| Phoenix International Limited | Information & communication | 2021 |
| Phrmcy Ltd | Wholesale & retail | 2024 |
| Picklevision Ltd | Information & communication | 2021 |
| Pieces L'Auto Ltd | Extraterritorial | 2020 |
| Piermont Solutions Ltd | Administrative & support | 2026 |
| Pilates by the Crown Ltd | Arts & recreation | 2026 |
| Pinecote Partners Limited | Professional & scientific | 2019 |
| Pinedale Limited | Real estate | 2014 |
| Pink Banana Studios London Ltd | Information & communication | 2011 |
| Pinpoint Media International Limited | Manufacturing | 2017 |
| Pinpoint Technology Limited | Information & communication | 2020 |
| Pinpoint Visualisation Limited | Information & communication | 2001 |
| Pivot IT Ltd | Information & communication | 2016 |
| Pixelgarden Limited | Professional & scientific | 2008 |
| Pixsellar-Technologies Ltd | Information & communication | 2020 |
| Pjms Properties Limited | Real estate | 2011 |
| PK Heating Ltd | Construction | 2023 |
| Planar Pete Ltd | Wholesale & retail | 2021 |
| Plascot Limited | Professional & scientific | 2013 |
| Platform for Urban Research and Architecture Ltd | Professional & scientific | 2010 |
| Playmaker Ltd | Wholesale & retail | 2018 |
| Plazmid Consulting Limited | Administrative & support | 2020 |
| Plexus Ventures Limited | Professional & scientific | 1999 |
| Plixer UK Limited | Information & communication | 2019 |
| Plummy's Ltd | Hospitality | 2018 |
| Plusoneevents Ltd | Arts & recreation | 2019 |
| PMC Consultancy Limited | Professional & scientific | 2026 |