| Ouchpotatoyork Ltd | Health & social care | 2025 |
| Oulholm Bridge Limited | Professional & scientific | 2025 |
| OUR Homeware Ltd | Wholesale & retail | 2021 |
| OUR House Ltd | Real estate | 2023 |
| OUR Little Friends Limited | Wholesale & retail | 2016 |
| OUR PMS Ltd | Extraterritorial | 2013 |
| Ouse LEA Freehold Limited | Households | 2020 |
| Ouse Lets Limited | Agriculture & fishing | 2006 |
| Ousebank Limited | Construction | 2023 |
| Ouseburn Services Limited | Real estate | 2008 |
| Ouseburn Village Store Ltd | Wholesale & retail | 2022 |
| Ousegill Business Park Ltd | Construction | 2020 |
| Ousevale Limited | Real estate | 2019 |
| Outcome Coaching Limited | Professional & scientific | 2018 |
| Outlier Technology Ltd | Professional & scientific | 2018 |
| Outlook Advisory Services Limited | Financial services | 2015 |
| Outset Works Limited | Information & communication | 2025 |
| Outsmart the Thief Limited | Manufacturing | 2005 |
| Outsource Vcse Support C.I.C. | Administrative & support | 2016 |
| Outsourced Compliance Services Ltd | Administrative & support | 2011 |
| Oval Innovations Ltd | Professional & scientific | 2023 |
| Oval Investment Group Ltd | Financial services | 2023 |
| Oval Renewables Ltd | Construction | 2019 |
| Oven Rescue York Ltd | Administrative & support | 2023 |
| Ovenwow Ltd | Administrative & support | 2018 |
| Over the Rainbow York C.I.C. | Hospitality | 2021 |
| Overclad Design Ltd | Professional & scientific | 2024 |
| Overington and Roberts Limited | Hospitality | 2014 |
| Overryd Ltd | Construction | 2013 |
| Overt Books Ltd | Information & communication | 2023 |
| Overthinkers Limited | Professional & scientific | 2014 |
| Ovinia Chase (Minster) Residents Management Company Limited | Households | 2025 |
| Owen Bell Associates Limited | Professional & scientific | 2019 |
| Owens Professional Partnership Limited | Administrative & support | 2007 |
| OWL Plumbing & Heating Ltd | Construction | 2020 |
| Owner Selling Ltd. | Professional & scientific | 1993 |
| Oxfordshire Land Limited | Extraterritorial | 1991 |
| Oxiris Ltd | Manufacturing | 2006 |
| Oxiris Property Ltd | Real estate | 2006 |
| Oxley Consulting Limited | Professional & scientific | 2024 |
| Oxstone Group Limited | Real estate | 2023 |
| Oxthorpe Dunhurst Limited | Professional & scientific | 2023 |
| Oxtoby Court Ltd | Real estate | 2012 |
| OZ Global Investments Ltd | Financial services | 2019 |
| Ozz-E-Utes Limited | Other services | 2026 |
| O’Brien Civil Engineering Management Ltd | Construction | 2024 |
| P & B Taverns Limited | Hospitality | 2017 |
| P & J Dowson Limited | Agriculture & fishing | 2015 |
| P & L Groundworks (Northern) Limited | Administrative & support | 2013 |
| P & M Mchugh Ltd | Professional & scientific | 2010 |
| P & R Farming Company | Agriculture & fishing | 2002 |
| P & S Atkinson Limited | Administrative & support | 2017 |
| P & SJ Solutions Limited | Professional & scientific | 2025 |
| P and B Plumbing and Heating Limited | Construction | 2019 |
| P B R Engineering Limited | Manufacturing | 2007 |
| P Boyz Limited | Administrative & support | 2005 |
| P Collier (Welding & Fabrication) Ltd | Mining & quarrying | 2010 |
| P D Mortimer Developments Limited | Construction | 2007 |
| P D Smith Properties Limited | Extraterritorial | 1993 |
| P Davey Limited | Administrative & support | 2018 |
| P Fletcher Contracting Ltd | Administrative & support | 2013 |
| P Gardham Holdings Limited | Financial services | 2023 |
| P Gardham Limited | Construction | 2003 |
| P M Garage Services Ltd | Wholesale & retail | 2020 |
| P Rudd Decorators Limited | Construction | 2007 |
| P Ryan Services Limited | Professional & scientific | 2007 |
| P S Memorials Ltd | Other services | 2022 |
| P Teasdale Limited | Hospitality | 2024 |
| P Walker Construction Services Limited | Construction | 2017 |
| P&B Property Ltd | Real estate | 2017 |
| P&O Property Ventures Ltd | Construction | 2022 |
| P,Tw & SR Rooke Ltd | Administrative & support | 2008 |
| P-51 Limited | Professional & scientific | 2009 |
| P. & F. Hawkswell Limited | Agriculture & fishing | 1976 |
| P. O. W. Camp 83 Limited | Arts & recreation | 1986 |
| P.B. Curran & Co (York) Limited | Financial services | 2003 |
| P.B. Curran & Co Holdings Limited | Financial services | 2007 |
| P.D. Clark Electrical Ltd | Construction | 2007 |
| P.D. Hughes Consultancy Services Limited | Professional & scientific | 2009 |
| P.J.F. Design Limited | Professional & scientific | 1998 |
| P.M.J. Masonry Limited | Manufacturing | 2007 |
| P.S. September Ltd | Transport & logistics | 2016 |
| P4P Ltd | Information & communication | 2018 |
| P6 Wellington Gate (Grove) Managment Company Limited | Households | 2024 |
| PA & KA Ltd | Real estate | 2018 |
| PA Deighton Ltd. | Construction | 2007 |
| PA Webb Properties Limited | Real estate | 2024 |
| PAB Cathodic Supply Limited | Professional & scientific | 2025 |
| PAB Joinery Limited | Manufacturing | 2018 |
| Pablo Carvacho Ltd | Professional & scientific | 2023 |
| PAC Productions Limited | Administrative & support | 2024 |
| Pace Property Consultants Ltd | Construction | 2022 |
| Pacemaker Developments Limited | Extraterritorial | 1961 |
| Paceworth Limited | Information & communication | 2014 |
| Pacific Bidco Limited | Other services | 2024 |
| Pacific Heights Plumbing and Heating Services Limited | Construction | 2014 |
| Pacific Holdco Limited | Financial services | 2024 |
| Pacific Topco Limited | Financial services | 2024 |
| Packapoo Ltd | Wholesale & retail | 2022 |
| PAD GAS Engineers Limited | Construction | 2002 |