| Ajdini Construction Ltd | Construction | 2025 |
| Ajks Associates Limited | Other services | 2016 |
| Ajoja Education Limited | Education | 2022 |
| Ajos Trust | Arts & recreation | 2014 |
| AJP Promotions Limited | Administrative & support | 2008 |
| AJW Enterprise Services Ltd | Information & communication | 2026 |
| Ajyal Foundation | Education | 2018 |
| Ajyal Foundation for Education | Education | 2018 |
| AK Architects Ltd | Administrative & support | 2003 |
| Akabza Property Investments Ltd | Real estate | 2025 |
| AKB Oxford Ltd | Hospitality | 2026 |
| AKG Dynamics Ltd. | Education | 2015 |
| Akim.Crepesomania Ltd | Hospitality | 2022 |
| AKJ Merge Ltd | Professional & scientific | 2020 |
| Akliberty Services Limited | Administrative & support | 2023 |
| Akoni Renewables UK Ltd | Energy | 2026 |
| Akoustics Limited | Professional & scientific | 2010 |
| Aksward Limited | Professional & scientific | 2005 |
| AL Amin Oxford Limited | Wholesale & retail | 2014 |
| AL Khaif Travel & Tours Ltd | Administrative & support | 2023 |
| AL Legal Services Ltd | Professional & scientific | 2019 |
| AL Muqeet Developers Limited | Administrative & support | 2017 |
| AL Shami Oxford Ltd | Hospitality | 2016 |
| Al-Salam Islamic Education Limited | Education | 2015 |
| Al-Taiar Enterprise Limited | Real estate | 2019 |
| Al-Taiar Medical Limited | Health & social care | 2015 |
| Aladdin Oxford Limited | Wholesale & retail | 1993 |
| Alam Distribution Ltd | Wholesale & retail | 2023 |
| Alam Mart Ltd | Wholesale & retail | 2026 |
| Alan Titchmarsh Limited | Professional & scientific | 1987 |
| Alaribe Chinaza Company Limited | Health & social care | 2025 |
| Alate Business Growth Ltd | Professional & scientific | 2018 |
| Alauda Consulting Limited | Professional & scientific | 2021 |
| Alazne UK Ltd | Administrative & support | 2025 |
| ALB Collections Apparel Ltd | Wholesale & retail | 2026 |
| ALB Medvoyage Ltd | Financial services | 2025 |
| Alban London Limited | Hospitality | 2022 |
| Albarakah Trade-Link (UK) Limited | Wholesale & retail | 1990 |
| Alberon Limited | Information & communication | 2006 |
| Albert ST Limited | Hospitality | 2023 |
| Albion Art Services Ltd | Wholesale & retail | 2017 |
| Albion Art Trading Ltd | Wholesale & retail | 2015 |
| Albion Consult Limited | Professional & scientific | 2019 |
| Albion Jeune Limited | Wholesale & retail | 2022 |
| Albion Techbio Ltd | Professional & scientific | 2025 |
| Albiorix Investments Limited | Financial services | 2024 |
| Alburn (Retail) Limited | Real estate | 2001 |
| Alc-Au-Lait Limited | Hospitality | 2013 |
| Alchem Pharma Ltd | Wholesale & retail | 2012 |
| Alchemy & Steam Ltd | Hospitality | 2025 |
| Aldates Community Transformation Initiatives | Health & social care | 2010 |
| Aldates Global Education Ltd | Education | 2024 |
| Alder Arts Ltd | Other services | 2025 |
| Alder Security Ltd | Administrative & support | 2016 |
| Aldertec Ltd | Other services | 2025 |
| Aldnorcorp Limited | Wholesale & retail | 2025 |
| Alema Ltd | Real estate | 2018 |
| Alex Boukas Ltd | Health & social care | 2025 |
| Alex Clinical Intelligence Ltd | Information & communication | 2025 |
| Alex Management Limited | Real estate | 2024 |
| Alex Spedition Limited | Transport & logistics | 2018 |
| Alex Top Barber Ltd | Other services | 2024 |
| Alex Wenham Limited | Manufacturing | 2016 |
| Alexander Court (Church Farm) Management Company Ltd | Households | 2026 |
| Alexander Finn Limited | Professional & scientific | 2006 |
| Alexandra a Tenovici Ltd | Health & social care | 2017 |
| Alexandra Lewis Family Law Limited | Professional & scientific | 2017 |
| Alexopoulos Family Products Ltd | Wholesale & retail | 2018 |
| Alextania Limited | Professional & scientific | 2001 |
| Alfa Intelligence & Innovative Indigo Solutions Ltd | Wholesale & retail | 2013 |
| Alfa Spa UK Ltd | Manufacturing | 2011 |
| Alfind Ltd | Wholesale & retail | 2023 |
| Alfresco Active Ltd | Arts & recreation | 2022 |
| Alftakins Care Ltd | Health & social care | 2026 |
| Alftakins Holdings Ltd | Financial services | 2026 |
| Algorithmic Governance CIC | Professional & scientific | 2025 |
| ALI & Mani Ltd | Wholesale & retail | 2023 |
| ALI and Harris Ltd | Hospitality | 2014 |
| ALI Inn Ltd | Hospitality | 2024 |
| ALI Script Ltd | Professional & scientific | 2025 |
| Alicha Ltd | Manufacturing | 2014 |
| Alifpost Ltd | Information & communication | 2020 |
| Aliisons Ltd | Wholesale & retail | 2023 |
| Alindene Limited | Professional & scientific | 1984 |
| Alison Earey Limited | Education | 2013 |
| Alispoir Ltd | Wholesale & retail | 2024 |
| Alistair Redhouse Mortgage Services Ltd | Financial services | 2026 |
| Aliwr Holding Limited | Administrative & support | 2021 |
| ALL Aboard Learning Ltd | Education | 2008 |
| ALL Cakes and Sizes Limited | Wholesale & retail | 2009 |
| ALL Day Retail Limited | Wholesale & retail | 2016 |
| ALL Duct Systems Holdings Limited | Financial services | 2021 |
| ALL Duct Systems Limited | Energy | 2013 |
| ALL Heart Care Limited | Administrative & support | 2017 |
| ALL Natural Cosmetics Ltd | Manufacturing | 2014 |
| ALL Safe Scaffolding Limited | Construction | 2013 |
| ALL Service One Limited | Administrative & support | 2022 |
| ALL Stars Dance Limited | Education | 2023 |
| ALL Stars Oxon Ltd | Hospitality | 2023 |
| ALL Type Roofing Ltd | Construction | 2025 |