| Openheaven Anointed Tabernacle Ltd | Other services | 2024 |
| Optima HR Ltd | Administrative & support | 2018 |
| OPTION24 Ltd | Transport & logistics | 2025 |
| Optomal Vision Ltd | Health & social care | 2009 |
| Opulent Projects Ltd | Construction | 2023 |
| Orchard Aesthetics Limited | Health & social care | 2010 |
| Orchard END Limited | Extraterritorial | 2003 |
| Orchard Limited | Arts & recreation | 1992 |
| Orchford Kitchens LLP | | 2010 |
| Ordinem Finance Ltd | Professional & scientific | 2014 |
| Oregan Property Limited | Real estate | 2021 |
| Organic Biltong Limited | Manufacturing | 2016 |
| ORI Rehab Limited | Information & communication | 2024 |
| Orla Morrin Services Ltd | Professional & scientific | 2024 |
| Orthentik Ltd | Wholesale & retail | 2026 |
| Orthodox Heritage Ltd | Manufacturing | 2025 |
| Ortomatic Ltd | Information & communication | 2026 |
| Orycle Ventures Limited | Professional & scientific | 2025 |
| Osmosis Press Limited | Information & communication | 2021 |
| Osprey Offshore(Incorporating Classic Offshore Power) Limited | Professional & scientific | 2023 |
| Otason UK Ltd | Professional & scientific | 2023 |
| Ouab Community Interest Company | Education | 2026 |
| OUR Web Services Ltd | Professional & scientific | 2022 |
| Outside Broadcasting Services Limited | Information & communication | 2013 |
| Ouyang Educ Global Ltd | Wholesale & retail | 2024 |
| Over the Sofa Ltd | Information & communication | 2021 |
| Overby Limited | Transport & logistics | 2004 |
| Oxford BUS & Coach Care Ltd | Wholesale & retail | 2020 |
| Oxford Filtration Limited | Manufacturing | 2000 |
| Oxford Lighting & Electrical Solutions Ltd | Construction | 2024 |
| Oxford ST Falafel Ltd | Hospitality | 2019 |
| OZJ Limited | Health & social care | 2023 |
| Ozones Construction Limited | Construction | 2024 |
| O’Brien Real Estate Limited | Extraterritorial | 2022 |
| P.A. Tree Care Limited | Agriculture & fishing | 2010 |
| P.Baldock & SON Limited | Other services | 1959 |
| P.Damian Ltd | Manufacturing | 2025 |
| P.G.M. Ductwork Services Ltd | Administrative & support | 2007 |
| P.T Judo Limited | Education | 2012 |
| P4DESIGN & Creative Ltd | Administrative & support | 2017 |
| Pack Pals Dog Walking Limited | Other services | 2017 |
| PACK2BASICS Ltd | Professional & scientific | 2015 |
| Paddocks View Estates Limited | Households | 2020 |
| Padeluxe UK Ltd | Arts & recreation | 2024 |
| Pagani Design Limited | Wholesale & retail | 2022 |
| PAL Serv Ltd | Construction | 2020 |
| PAN Solutions Ltd | Information & communication | 2024 |
| Papaya Ltd | Professional & scientific | 2023 |
| Paper Design Consulting Ltd | Professional & scientific | 2023 |
| Papercut Services UK Limited | Administrative & support | 2016 |
| Paragon Freight Management (Holdings) Limited | Transport & logistics | 2022 |
| Paragon Freight Management Limited | Transport & logistics | 1990 |
| Paragon Pro Cleaning Ltd | Administrative & support | 2025 |
| Parallel Systems Limited | Information & communication | 1997 |
| Paramount Tree Care Limited | Administrative & support | 2018 |
| Paratus AMC Limited | Financial services | 1998 |
| Parcay Investments Limited | Real estate | 2021 |
| Paringa Ltd | Public administration | 2024 |
| Parizma Group Limited | Administrative & support | 2016 |
| Park Lane Prestige Ltd | Wholesale & retail | 2011 |
| Parkash Ltd | Education | 2022 |
| Parking & Property Management Ltd | Administrative & support | 2013 |
| Parkinson Property Group Ltd | Real estate | 2024 |
| Parkshore Limited | Transport & logistics | 2012 |
| PAT Clarke Ltd | Professional & scientific | 2025 |
| Patient Primary Limited | Extraterritorial | 2016 |
| Patrick Featherstone Ltd | Administrative & support | 2017 |
| Patrick Nicholas Properties Ltd | Real estate | 2019 |
| Patronas Roofing & Facades Ltd | Construction | 2021 |
| Patsteve Ltd | Health & social care | 2012 |
| Patten Screen Print Limited | Manufacturing | 2002 |
| Paul Mitchell Building Ltd | Extraterritorial | 2017 |
| Paul Mitchell Estates Ltd | Real estate | 2013 |
| Paul Mitchell Land Ltd | Extraterritorial | 2017 |
| Paulflo Healthcare Ltd | Health & social care | 2014 |
| PAV Creations Ltd | Information & communication | 2021 |
| Pawansutra Limited | Hospitality | 2024 |
| Pawer Limited | Administrative & support | 2016 |
| PC Cars UK PVT Ltd | Wholesale & retail | 2019 |
| PCS Wireless Mobile UK Ltd | Wholesale & retail | 2021 |
| PCS Wireless UK Limited | Wholesale & retail | 2019 |
| PD Collections Ltd | Transport & logistics | 2025 |
| PD Material Handling Limited | Manufacturing | 2017 |
| PDP Logistics Ltd | Transport & logistics | 2025 |
| Peabody Solutions Ltd | Professional & scientific | 2025 |
| Peac (BF1) Limited | Financial services | 1988 |
| Peac (UK) Limited | Financial services | 1995 |
| Peac Business Finance Holdings Limited | Financial services | 2021 |
| Peac Business Finance Limited | Financial services | 1967 |
| Peac Holdings (UK) Limited | Financial services | 2015 |
| Peac Solutions Limited | Extraterritorial | 2020 |
| Peakexit Limited | Professional & scientific | 2020 |
| Pearce Mayfield Training Limited | Education | 2014 |
| Pearl & ASH Limited | Professional & scientific | 2017 |
| Pebble Bridge Ltd | Professional & scientific | 2026 |
| Peddlesmart Limited | Manufacturing | 2015 |
| Pegasus Consulting, London UK, Ltd | Professional & scientific | 2024 |
| Pegasus Home Improvements Ltd | Professional & scientific | 2026 |
| Pelikos Limited | Administrative & support | 2017 |
| Pelina Services Ltd | Administrative & support | 2023 |