| Neosa Ltd | Wholesale & retail | 2026 |
| Neva KIP Ltd | Hospitality | 2017 |
| New Economics Knowledge Services Ltd | Information & communication | 2016 |
| New Energy Consulting Limited | Professional & scientific | 2017 |
| New Park Farm Developments Limited | Construction | 2016 |
| New World Energy (Oxfordshire) Ltd | Construction | 2023 |
| Newcombe Court (Oxford) Limited | Households | 2007 |
| Newcycle Investments Limited | Administrative & support | 2002 |
| Newcycle Property Limited | Real estate | 2024 |
| Newlands Court Management Company Limited | Households | 2004 |
| Nhmk Smile Ltd | Health & social care | 2025 |
| NI NE NO Investments Limited | Real estate | 2022 |
| Nick Brown (Roofing Contractor) Limited | Construction | 2003 |
| Nicollane Ltd | Other services | 2012 |
| Nigel Belcher Turf & Paving Limited | Administrative & support | 2015 |
| Nightingale Management Group Ltd | Professional & scientific | 2019 |
| NJF Shopfitting and Construction Limited | Construction | 2014 |
| NJL Consultancies Ltd | Construction | 2022 |
| Norglebe Limited | Households | 1980 |
| Norham END (Oxford) Management Company Limited | Households | 1978 |
| NORNOM4 Limited | Administrative & support | 2020 |
| North Aston Farm Shop Ltd | Wholesale & retail | 2025 |
| North Oxford Developments Ltd | Construction | 2021 |
| North Oxford Plumbing & Heating Ltd | Extraterritorial | 2024 |
| North Oxon Land Rovers Limited | Extraterritorial | 2011 |
| Northern Lights Capital Partners (UK) Limited | Financial services | 2008 |
| Northmoor Park Management Company Ltd | Real estate | 2023 |
| Nova Capital Xxii Ltd | Financial services | 2025 |
| Nova Xxii Ltd | Professional & scientific | 2025 |
| Noxera Healthcare Limited | Information & communication | 2026 |
| Nucard Properties Limited | Professional & scientific | 1921 |
| Number 18 (Kidlington) Management Company Limited | Households | 2010 |
| Nursery Close Residents' Association Limited | Real estate | 1968 |
| Nutriodol Supplements Ltd | Administrative & support | 2014 |
| NYR Datalytics Limited | Information & communication | 2016 |
| O & O Electrical Limited | Construction | 2005 |
| O&O Investment Properties Limited | Construction | 2010 |
| O.J.Squire Ltd | Other services | 2024 |
| Obeya Ltd | Wholesale & retail | 2017 |
| Occupational Health and Screening Services Limited | Health & social care | 2014 |
| Ockham Court Management Co (NO.3) Limited | Households | 1987 |
| Ockham Court Management Co. (NO 2) Limited | Households | 1987 |
| Ockham Court Management Company (Number One) Limited | Households | 1985 |
| OCN Rentals Limited | Real estate | 2023 |
| ODD Emporium Ltd | Wholesale & retail | 2022 |
| OGM (SW) Limited | Manufacturing | 2017 |
| Old Town Barbers Oxon Ltd | Other services | 2020 |
| OM & Bass Limited | Arts & recreation | 2019 |
| Omgreen Ltd | Real estate | 2024 |
| Omni Air Conditioning Ltd | Other services | 2017 |
| Omnitech Solutions Limited | Information & communication | 2014 |
| One Eighty Developments Ltd | Real estate | 2026 |
| One Endurance Ltd | Arts & recreation | 2020 |
| Onea Building Solutions Ltd | Construction | 2019 |
| Opcharge UK Holding Limited | Manufacturing | 2023 |
| Opcharge UK SPV 1 Limited | Manufacturing | 2023 |
| OPER8 Global Limited | Information & communication | 2019 |
| OPER8 Group Holdings Limited | Financial services | 2024 |
| Oprima Limited | Manufacturing | 2002 |
| Optoweld Ltd | Wholesale & retail | 2024 |
| Orion Property Homes Ltd | Real estate | 2022 |
| Osney Court Management Company Limited | Households | 1999 |
| OTH (Kidlington) Ltd | Hospitality | 2017 |
| OVI Transport and Logistics Ltd | Transport & logistics | 2025 |
| Ovisher Kidlington Ltd | Hospitality | 2026 |
| Ovisher Restaurant Ltd | Hospitality | 2016 |
| Owen Greenings & Mumford Limited | Manufacturing | 1962 |
| OX IT Solutions Limited | Information & communication | 2016 |
| OX N Chicks Ltd | Hospitality | 2025 |
| OX Scaffold Ltd | Construction | 2018 |
| Oxair Limited | Energy | 2020 |
| Oxford Aeroplane Company Limited | Other services | 2002 |
| Oxford Airline Training Limited | Education | 2025 |
| Oxford Alarm Company Ltd | Administrative & support | 2016 |
| Oxford Antiques & Curios Ltd | Wholesale & retail | 2025 |
| Oxford Applied Technology Ltd. | Professional & scientific | 2001 |
| Oxford Aviation Training Solutions Ltd | Education | 2018 |
| Oxford BED and Breakfast Limited | Hospitality | 2018 |
| Oxford Builders Limited | Construction | 2023 |
| Oxford CAB Ltd | Transport & logistics | 2021 |
| Oxford Capital Strategies Ltd | Information & communication | 2011 |
| Oxford Chiropractors Ltd | Health & social care | 2014 |
| Oxford Commercial Surveyors Limited | Professional & scientific | 2025 |
| Oxford Creative Technology Ltd | Professional & scientific | 2009 |
| Oxford Critical Care Ltd | Real estate | 2011 |
| Oxford Dharma Centre CIC | Information & communication | 2025 |
| Oxford Diocesan Board of Education | Education | 2009 |
| Oxford Edens LLP | | 2015 |
| Oxford Education and Tuition Limited | Education | 2023 |
| Oxford Elite Education Ltd | Education | 2016 |
| Oxford Elite Homestays Ltd | Hospitality | 2025 |
| Oxford Energetics Limited | Manufacturing | 2020 |
| Oxford Fetal Medicine Limited | Health & social care | 2002 |
| Oxford First AID Training Limited | Education | 2025 |
| Oxford Flight Savers Limited | Administrative & support | 2012 |
| Oxford Gene Technology (Operations) Ltd | Professional & scientific | 1999 |
| Oxford Gene Technology (Southern) Limited | Professional & scientific | 1996 |
| Oxford Gene Technology IP Limited | Professional & scientific | 1999 |
| Oxford Gene Technology Limited | Professional & scientific | 1995 |
| Oxford Global Consultants Ltd | Professional & scientific | 2019 |