| Brookmans Trading Limited | Construction | 2016 |
| Brookos of Botley Limited | Wholesale & retail | 2004 |
| Brooks Cars Ltd | Transport & logistics | 2025 |
| Brooks Multi Trade Ltd | Construction | 2021 |
| Brookside Trading LLP | | 2018 |
| Brother Oxford Limited | Hospitality | 2020 |
| Brothers 11 Car Wash Ltd | Administrative & support | 2025 |
| Brow Lodge Limited | Other services | 2015 |
| Brown & SON Tiling Contractors Limited | Construction | 2015 |
| Brown Hare Farming Ltd | Agriculture & fishing | 2016 |
| Brown Oxon Ltd | Transport & logistics | 2019 |
| Browns Cafe (Oxford) Limited | Hospitality | 2011 |
| Brownstone Homes Limited | Construction | 2014 |
| Bruce Garden Services Ltd | Wholesale & retail | 2023 |
| Bruern LLP | | 2009 |
| Bruin Cafe Ltd | Hospitality | 2019 |
| Brunel House (Thatcham) Management Limited | Real estate | 2006 |
| Bruno Psychiatry Ltd | Health & social care | 2020 |
| Brunwin Ltd | Real estate | 2018 |
| BRV Volume Limited | Extraterritorial | 2007 |
| Bryant Plastering Services Limited | Construction | 2017 |
| Bsil Property Ltd | Real estate | 2021 |
| BSN Management Limited | Professional & scientific | 2012 |
| Bsox Limited | Real estate | 2003 |
| Btemi Ayeni Ltd | Other services | 2018 |
| BTS Posture Academy Ltd | Education | 2026 |
| Buchanan Lighting Limited | Wholesale & retail | 2014 |
| Buckets Tech Ltd | Information & communication | 2023 |
| Buckingham Place Management Company Limited | Households | 1988 |
| Buckinghamshire Care Providers Association Limited | Administrative & support | 2007 |
| Buckinghamshire Chauffeured Services Limited | Transport & logistics | 2020 |
| Buckland Court (Kidlington) Residents Company Limited | Hospitality | 1993 |
| Buckwood (Environmental) Ltd | Manufacturing | 2021 |
| Budda Ltd | Hospitality | 2022 |
| Budstar Limited | Financial services | 2010 |
| Buildando Limited | Construction | 2026 |
| Buildavenue Limited | Professional & scientific | 2005 |
| Built in Oxford Ltd | Construction | 2025 |
| Bulkpro Global Ltd | Wholesale & retail | 2025 |
| Bulldog Locations Ltd | Administrative & support | 2021 |
| Bulmershe Medical Limited | Health & social care | 2019 |
| Bunting Accountants Limited | Professional & scientific | 2003 |
| Burchell Design Limited | Administrative & support | 2021 |
| Burnham Investments Limited | Construction | 1976 |
| Burning Blue Limited | Construction | 1998 |
| Burra Close Freehold Limited | Households | 2025 |
| Burra Close Owners Resident Association Limited | Households | 2022 |
| Burrows & Hare Limited | Wholesale & retail | 2015 |
| Burst Design Ltd | Professional & scientific | 2020 |
| Bury's Dryanstore Limited | Real estate | 1956 |
| Bury's Holdings Limited | Extraterritorial | 2017 |
| Bury's Transport (Maxim) Limited | Agriculture & fishing | 1960 |
| Bushfield Limited | Manufacturing | 1974 |
| Bushnell Close Headington (Oxford) Management Company Limited | Households | 2004 |
| Busibytes Limited | Information & communication | 1999 |
| Business Assistance Limited | Extraterritorial | 2024 |
| Business Intelligence Focus Limited | Information & communication | 2018 |
| Business Mechanics Limited | Professional & scientific | 1999 |
| Business Offers Limited | Professional & scientific | 2000 |
| Business Travel Management Limited | Professional & scientific | 2000 |
| Butler & Butler Investments Ltd | Real estate | 2023 |
| Butler Close (Management) Limited | Households | 1981 |
| Butt Freight Services Limited | Transport & logistics | 2012 |
| Butter Works Studio Ltd | Professional & scientific | 2025 |
| Buylytics Ltd | Wholesale & retail | 2020 |
| Buzy Beez Tyres and Exhausts Ltd | Wholesale & retail | 2019 |
| Buzz Advisory Ltd | Professional & scientific | 2024 |
| Buzz KIT Ltd | Professional & scientific | 2024 |
| Buzziful Ltd | Education | 2025 |
| Buzzlan Media Group Ltd | Wholesale & retail | 2019 |
| Bvbiomedical Limited | Professional & scientific | 2020 |
| Bvrio Holdings Limited | Professional & scientific | 2017 |
| Bvrio UK Limited | Professional & scientific | 2018 |
| BW Resources Limited | Information & communication | 2000 |
| BWR Medical Limited | Health & social care | 2016 |
| Bxaleem Limited | Wholesale & retail | 2024 |
| C and F Garden Services Ltd | Administrative & support | 2024 |
| C Douglas Midlands Ltd | Administrative & support | 2017 |
| C House Ltd | Wholesale & retail | 2007 |
| C Mitchell Consultancy Limited | Professional & scientific | 2026 |
| C R Oxford Motors Limited | Wholesale & retail | 2021 |
| C R White Electrical Limited | Construction | 2007 |
| C S Simpson Limited | Construction | 2011 |
| C&M Zugaj Ltd | Professional & scientific | 2013 |
| C&S Blackwood Limited | | 2010 |
| C. K. Patel Limited | Health & social care | 2002 |
| C.E. Hill & Co. Ltd | Professional & scientific | 2002 |
| C.J.De'Ath Investments Limited | Real estate | 1962 |
| C.K. Psychology Ltd | Health & social care | 2025 |
| C.L.J. Logistics (UK) Limited | Wholesale & retail | 2008 |
| C.O.V Property Investments Limited | Real estate | 2024 |
| C.P.R.E. Oxfordshire Buildings Preservation Trust Limited | Health & social care | 1971 |
| C3D Community CIC | Other services | 2024 |
| C4 Traders Limited | Wholesale & retail | 2024 |
| C7 Solutions Limited | Information & communication | 2002 |
| CA Technical Software Ltd | Information & communication | 2013 |
| Cablefree Networks Limited | Information & communication | 2018 |
| Cache Limited | Information & communication | 2008 |
| Cactus Caravan Ltd | Hospitality | 2026 |
| CAD Drawings Oxford Ltd | Professional & scientific | 2025 |