| Outsideclinic JVP 09 Ltd | Health & social care | 2022 |
| Outsideclinic JVP 10 Ltd | Health & social care | 2022 |
| Outsideclinic JVP 11 Ltd | Health & social care | 2022 |
| Outsideclinic JVP 13 Ltd | Health & social care | 2022 |
| Outsideclinic JVP 14 Ltd | Health & social care | 2022 |
| Outsideclinic JVP 15 Ltd | Health & social care | 2022 |
| Outsideclinic JVP 16 Ltd | Health & social care | 2022 |
| Outsideclinic JVP 17 Ltd | Health & social care | 2022 |
| Outsideclinic JVP 18 Ltd | Health & social care | 2022 |
| Outsideclinic JVP 19 Ltd | Health & social care | 2022 |
| Outsideclinic JVP 20 Ltd | Health & social care | 2022 |
| Outsideclinic JVP 21 Ltd | Health & social care | 2025 |
| Outsideclinic JVP 23 Ltd | Health & social care | 2025 |
| Outsideclinic JVP 24 Ltd | Health & social care | 2026 |
| Outsideclinic JVP 25 Ltd | Health & social care | 2026 |
| Outsideclinic Limited | Health & social care | 1993 |
| Outsideclinic Services Limited | Wholesale & retail | 2021 |
| OV Management Co Limited | Households | 2023 |
| Oval Recruit Limited | Administrative & support | 2009 |
| Ovar Comer Ltd | Real estate | 2025 |
| Over the Top Limited | Extraterritorial | 2003 |
| Overcomer Literature Trust Limited | Information & communication | 1928 |
| Overdrive Pictures Ltd | Information & communication | 2016 |
| Overload Electrical Ltd | Construction | 2025 |
| Overpowered Software Limited | Information & communication | 2023 |
| OWE Group Ltd | Construction | 2026 |
| Owen Estates Ltd | Real estate | 2019 |
| Owen James Properties Limited | Real estate | 2017 |
| Owen Rail Engineering Ltd | Professional & scientific | 2024 |
| Owen Services Ltd | Agriculture & fishing | 2024 |
| Owen Sound Limited | Information & communication | 2013 |
| Owens World Community Interest Company | Professional & scientific | 2023 |
| Own Words Ltd | Education | 2025 |
| Oxbridge Content Ltd | Administrative & support | 2020 |
| Oxcamb Investments Limited | Financial services | 1999 |
| Oxford Business Park (North) Management Limited | Real estate | 1994 |
| Oxford Business Park (South) Management Limited | Real estate | 1994 |
| Oxford Exteriors Ltd | Administrative & support | 2019 |
| Oxford Food Anatomy Ltd | Hospitality | 2025 |
| Oxford House (Cirencester) Management Company Limited | Households | 1985 |
| Oxford Style Ltd | Professional & scientific | 2013 |
| Oxford Table Catering Limited | Hospitality | 2026 |
| Oxfordshire Decking Ltd | Manufacturing | 2025 |
| Oxfordshire Driveways and Patios Limited | Construction | 2024 |
| Oxfordshire Vehicle Services Ltd | Wholesale & retail | 2024 |
| Oxgen Academy Ltd | Wholesale & retail | 2025 |
| Oxring Limited | Wholesale & retail | 1986 |
| Oxwash Big Blue I Ltd | Other services | 2022 |
| Oymak Ltd | Hospitality | 2018 |
| OZ Barbers Ltd | Other services | 2025 |
| Ozbric Limited | Construction | 2009 |
| Ozeba Limited | Health & social care | 2025 |
| Ozone Consultancy Ltd | Other services | 2026 |
| P & B Maintenance LLP | | 2012 |
| P & D Ventures Limited | Information & communication | 2017 |
| P & I Property Maintenance Limited | Construction | 2023 |
| P & P Glass Limited | Construction | 1988 |
| P & P Holdings Limited | Professional & scientific | 2007 |
| P & R Insurance Services | | 1985 |
| P a Matthews & Co Limited | Construction | 2003 |
| P and J Stratton Investments Ltd | Agriculture & fishing | 2015 |
| P Brzykcy Limited | Transport & logistics | 2017 |
| P C Barton Ltd | Education | 2013 |
| P G Events Limited | Construction | 2007 |
| P G W Electrical Limited | Construction | 2012 |
| P J Gale & SON Ltd | Construction | 2013 |
| P J Hardy Consulting Ltd | Professional & scientific | 2025 |
| P J O Engineering Limited | Manufacturing | 2000 |
| P Jackson Financial Services Ltd | Professional & scientific | 2009 |
| P K Transport (Swindon) Limited | Transport & logistics | 2002 |
| P L R Limited | Wholesale & retail | 1984 |
| P M Joseph Limited | Agriculture & fishing | 2008 |
| P M Solar and Battery Solutions Limited | Construction | 2023 |
| P Punjab Ltd | Transport & logistics | 2021 |
| P S Ansell Plumbing & Heating Ltd | Construction | 2015 |
| P T Mills Ltd | Professional & scientific | 2020 |
| P&A Constructions Limited | Construction | 2020 |
| P&A Plumbing Limited | Construction | 2018 |
| P&B Accounts Ltd | Professional & scientific | 2025 |
| P&G Autos Ltd | Wholesale & retail | 2022 |
| P&Y Property Investments Ltd | Real estate | 2019 |
| P. Booth Construction Limited | Construction | 2010 |
| P.A.S. Construction Limited | Professional & scientific | 1998 |
| P.H. Builders (Aldbourne) Limited | Real estate | 1997 |
| P.P. Hobbs Limited | Professional & scientific | 2012 |
| P.P.F. Roofing & Property Limited | Construction | 2017 |
| P2D (UK) Limited | Information & communication | 2004 |
| P2DLT Ltd | Information & communication | 2018 |
| PA and Project Support Ltd | Administrative & support | 2018 |
| PA2012 Limited | Wholesale & retail | 2012 |
| PAA Investments Ltd | Real estate | 2024 |
| Pacd Drylining Ltd | Construction | 2024 |
| Pace Intl Ltd | Wholesale & retail | 2023 |
| Packnbrand Ltd | Administrative & support | 2025 |
| Packs Meet Customers Ltd | Transport & logistics | 2026 |
| Pacoga Trans Ltd | Transport & logistics | 2018 |
| Pacreation Ltd | Administrative & support | 2011 |
| Padel Nova Limited | Real estate | 2025 |
| Padwell Real Estate Limited | Real estate | 2023 |
| Pafrm Limited | Professional & scientific | 2010 |