| Alla Car Wash & Valeting Ltd | Administrative & support | 2024 |
| Allbreeze Limited | Households | 2013 |
| Allelectrics Limited | Wholesale & retail | 1987 |
| Allen Associates (Oxford) Limited | Administrative & support | 2001 |
| Allrx Healthcare Limited | Wholesale & retail | 2024 |
| Allsafe Holdings Limited | Financial services | 2018 |
| Allways Trade & Build Limited | Construction | 2024 |
| ALM Connect Limited | Wholesale & retail | 2024 |
| Alma Place Limited | Professional & scientific | 2002 |
| Almomax Ltd | Wholesale & retail | 2019 |
| ALN Developments Ltd | Construction | 2025 |
| ALN Properties Ltd | Real estate | 2018 |
| Alpeggi Limited | Construction | 2017 |
| Alpha & Crown Ltd | Hospitality | 2025 |
| Alpha 1 Training and Consultancy Services Limited | Professional & scientific | 2019 |
| Alpha Academic Ltd | Financial services | 2015 |
| Alpha Academy Oxford Ltd | Arts & recreation | 2021 |
| Alpha Assemble Ltd | Wholesale & retail | 2024 |
| Alpha Driveways & Roofing Ltd | Construction | 2025 |
| Alpha Home MG Ltd | Real estate | 2025 |
| Alpha Homecare Ltd | Health & social care | 2025 |
| Alpha Nationwide Delivery Ltd | Transport & logistics | 2025 |
| Alpha of Oxford Cleaning Services Ltd | Administrative & support | 2019 |
| Alpha RW Limited | Other services | 2014 |
| Alpha Supported Living Services Ltd | Health & social care | 2024 |
| Alphafoodie Limited | Other services | 2017 |
| Alpin Restaurant Ltd | Other services | 2024 |
| Alpine Oxon Ltd | Hospitality | 2025 |
| ALS Construction (Oxford) Ltd | Construction | 2011 |
| Alsandp Ltd | Health & social care | 2024 |
| Alshebli Limited | Administrative & support | 2019 |
| Alsi Chauffeurs Ltd | Transport & logistics | 2026 |
| Also ME Media Ltd | Information & communication | 2025 |
| Alta Homes (Finstock) Ltd | Construction | 2026 |
| Alta Scientia Ltd. | Professional & scientific | 2009 |
| Altalto Immingham Holdings Limited | Financial services | 2018 |
| Altalto Immingham Limited | Professional & scientific | 2018 |
| Altalto Limited | Financial services | 2018 |
| Altereon Ltd | Health & social care | 2026 |
| Alternative Cars Limited | Manufacturing | 2003 |
| Alternative Travel Flights Limited | Administrative & support | 1996 |
| Alternative Travel Group (Holdings) Limited | Professional & scientific | 1985 |
| Alternative Travel Group Limited | Administrative & support | 1979 |
| Altius Coaching and Consulting Ltd | Professional & scientific | 2015 |
| Altura Pro Limited | Construction | 1995 |
| Aluminium Construction Ltd | Construction | 2020 |
| Alveogene Limited | Professional & scientific | 2022 |
| Alvet Vacuum Coatings Limited | Professional & scientific | 2016 |
| Alvis Owner Club Limited | Arts & recreation | 2000 |
| Alvius Ltd | Information & communication | 2013 |
| Always Spotless Ltd | Administrative & support | 2023 |
| Alyany Services Ltd | Administrative & support | 2025 |
| AM Bouka Ltd | Construction | 2022 |
| AM Building Services Oxon Ltd | Construction | 2023 |
| AM Concierge Ltd | Other services | 2025 |
| AM Crafts Limited | Wholesale & retail | 2026 |
| AM Gafcon Limited | Other services | 2008 |
| AM Motors Prestige Ltd | Wholesale & retail | 2024 |
| Amadeus Software Limited | Information & communication | 1991 |
| Amak Secure Services Limited | Administrative & support | 2021 |
| Amanda Catering Services Ltd | Wholesale & retail | 2026 |
| Amanda Wilkins Buying Agent & Property Finder Ltd | Real estate | 2023 |
| Amari Limited | Real estate | 2025 |
| Amazing Cleaning Services Oxford Ltd | Administrative & support | 2023 |
| Amazing Feet Limited | Information & communication | 1993 |
| Amazingoz Ltd | Wholesale & retail | 2025 |
| Amazon Ltd | Professional & scientific | 2017 |
| Amazon Oxford Ltd | Hospitality | 2015 |
| Amazonflip Ltd | Transport & logistics | 2026 |
| Ambassadoor Industrial Door Systems Limited | Construction | 2005 |
| Amber Clare Aesthetics Limited | Other services | 2025 |
| Amberbrooke Advisers Ltd | Professional & scientific | 2021 |
| Amber’S Aesthetics Limited | Other services | 2026 |
| Ambient Vision Limited | Information & communication | 2023 |
| Ambleside Life Ltd | Information & communication | 2026 |
| AMC Media and Design Limited | Information & communication | 2010 |
| Amelia Spencer Limited | Arts & recreation | 2021 |
| Amelie's Online Lettings Limited | Real estate | 2017 |
| Amelie's Online Ltd | Real estate | 2012 |
| Amelies Online Land and New Homes Limited | Real estate | 2024 |
| Ameliorate Children's Services Ltd | Health & social care | 2021 |
| Amesto Payroll Services (UK) Ltd | Professional & scientific | 2025 |
| Amethyst Informatics Limited | Administrative & support | 2012 |
| Amherst Capital (GP) Limited | Professional & scientific | 2025 |
| Amherst Capital LP | | 2025 |
| AMI K Gardenig Limited | Administrative & support | 2026 |
| Amicris Ltd | Hospitality | 2024 |
| Amin Oxford Ltd | Construction | 2025 |
| Amin Property Ltd | Real estate | 2018 |
| Amin TM Ltd | Health & social care | 2015 |
| AMJ Equities Limited | Real estate | 2021 |
| AMJ Group Limited | Transport & logistics | 2017 |
| AMJ Logistics Limited | Transport & logistics | 2022 |
| AMJ Oxford Ltd | Construction | 2025 |
| AMJ Residential Ltd | Real estate | 2022 |
| AMK Consulting Ltd | Professional & scientific | 2008 |
| Ammu C Ltd | Health & social care | 2025 |
| AMO Vittoria Ltd | Hospitality | 2023 |
| Amoai Technologies Ltd | Information & communication | 2019 |
| Amonova Limited | Professional & scientific | 2024 |