| Bespoke Alterations Oxford LLP | | 2020 |
| Bespoke by Petras Ltd | Construction | 2024 |
| Bespoke Carpentry Solutions Oxford Ltd | Manufacturing | 2024 |
| Bespoke Glazing Solutions Limited | Construction | 2012 |
| Best Financial Planning Ltd | Financial services | 2006 |
| Best Nest Hatcheries Limited | Agriculture & fishing | 1991 |
| Beta RW Limited | Other services | 2014 |
| Betgate Steelwork Ltd | Administrative & support | 2016 |
| Bethel Cars Oxford Ltd | Transport & logistics | 2023 |
| Better Britain | Professional & scientific | 2011 |
| Bettercare Skills Ltd. | Information & communication | 2013 |
| Betts Medical Limited | Health & social care | 2012 |
| Betty Lane Ltd | Information & communication | 2023 |
| Bettymakeover Ltd | Other services | 2025 |
| Beyond 2050 Limited | Administrative & support | 2020 |
| Beyond Global Events Ltd | Construction | 2024 |
| Beyond Orbital Ltd | Transport & logistics | 2025 |
| Beyond the Negative Limited | Other services | 2005 |
| Beyondfence Ltd | Manufacturing | 2025 |
| BGR Nominees Limited | Professional & scientific | 2015 |
| BH Posture Management Ltd | Health & social care | 2025 |
| Bhairavaa Properties Limited | Real estate | 2026 |
| Bhandari Properties Limited | Real estate | 2023 |
| Bhatia CMC Biotech Consulting Limited | Professional & scientific | 2025 |
| BHB Technology Consultants Ltd | Information & communication | 2021 |
| Bhpl Ltd | Wholesale & retail | 2017 |
| BHS Estates Limited | Real estate | 2020 |
| BHW Group Oxford Limited | Financial services | 2016 |
| BHW Refrigeration & Air Conditioning Limited | Construction | 2004 |
| Biarnes Limited | Health & social care | 2019 |
| Bibsol Ltd | Education | 2024 |
| Bicester Pizza House Limited | Households | 2025 |
| Big Bang Instruments Limited | Manufacturing | 2023 |
| Big Bear Maintenance Limited | Real estate | 2024 |
| Big Bear Rentals Limited | Real estate | 2024 |
| Big Foot Communications Limited | Professional & scientific | 2018 |
| Big Logistics Limited | Transport & logistics | 2020 |
| Big OX Storage Ltd | Real estate | 2026 |
| Big Picture Studio Entertainment Design Ltd | Administrative & support | 2011 |
| Big Top Design Limited | Administrative & support | 2000 |
| Bigberry Digital Limited | Administrative & support | 2010 |
| Biggerplate Ltd | Information & communication | 2006 |
| Bigupdata Ltd | Information & communication | 2014 |
| Bike Safe, West Oxfordshire Limited | Health & social care | 2011 |
| Billingham and Young Limited | Construction | 1980 |
| BIM Global Solutions UK Ltd | Information & communication | 2025 |
| Bimbleton Advisory Limited | Professional & scientific | 2026 |
| Binsey Green Holdings Limited | Extraterritorial | 2004 |
| Bioarchitech Ltd | Professional & scientific | 2014 |
| Biodata Insights Ltd | Information & communication | 2026 |
| Biofutures Consulting Limited | Professional & scientific | 2023 |
| Biogenomics Ltd | Professional & scientific | 2024 |
| Biolligence Limited | Professional & scientific | 2024 |
| Biomicrogels UK Limited | Water & waste | 2015 |
| Biopharmavantage Limited | Professional & scientific | 2014 |
| Bioscan (UK) Limited | Administrative & support | 1984 |
| Biotec-Fertility Ltd | Professional & scientific | 2022 |
| Biotechgen Limited | Professional & scientific | 2000 |
| Biotix Ltd. | Professional & scientific | 2021 |
| Birch Bracken Limited | Construction | 2021 |
| Birker Ltd | Real estate | 2006 |
| Bishop's Stortford MS Sushi Ltd | Wholesale & retail | 2024 |
| Bishop’S Field (Tingewick) Management Co Limited | Households | 2022 |
| Bison Enterprise Limited | Construction | 2021 |
| Bison Management Ltd | Professional & scientific | 2022 |
| BIT by BIT Education Limited | Education | 2025 |
| Biterush Express Ltd | Hospitality | 2025 |
| Bitmoti Security Solutions Limited | Information & communication | 2024 |
| BJL Kuomase CIC | Education | 2025 |
| BK Construction Group Ltd | Construction | 2023 |
| Black Box Trading Technology Ltd | Information & communication | 2020 |
| Black Cat’S Crypt Ltd | Wholesale & retail | 2024 |
| Black COW Technology Limited | Information & communication | 2013 |
| Black Lake Group Limited | Professional & scientific | 2024 |
| Black Nest IT Limited | Information & communication | 2017 |
| Black Opal Ltd | Administrative & support | 2025 |
| Black Stone Property Oxford Ltd | Real estate | 2020 |
| Blackbird Campbell Limited | Information & communication | 2017 |
| Blackbird Leys 4 Life CIC | Education | 2024 |
| Blackditch Farms Limited | Financial services | 2017 |
| Blackmount Group Ltd | Professional & scientific | 2026 |
| Blackridge Commercial Limited | Real estate | 2020 |
| Blackridge Estates 2 Limited | Real estate | 2023 |
| Blackridge Estates Limited | Real estate | 2018 |
| Blackridge Oxford Ltd | Financial services | 2022 |
| Blackridge South Parade Ltd | Real estate | 2022 |
| Blackstream Limited | Hospitality | 2002 |
| Blake Evans & Co Limited | Professional & scientific | 2016 |
| Blakes Oak Management Company Limited | Households | 1986 |
| Blazier S Limited | Real estate | 2020 |
| Bleisure Global Limited | Administrative & support | 2018 |
| Blenford Ltd | Construction | 2015 |
| Blenheim Anaesthetic Services Limited | Health & social care | 2015 |
| Blenheim Associates Ltd | Information & communication | 2025 |
| Blenheim Plumbing & Heating Ltd | Construction | 2020 |
| Blenheim Road (Kidlington) Management Company Limited | Households | 1974 |
| Blenheim Sandwich Co. Ltd | Hospitality | 2019 |
| Blinding Sunrise Productions Ltd | Information & communication | 2018 |
| BLINDS4U Oxford Ltd | Construction | 2025 |
| Blitz Consulting Limited | Information & communication | 2014 |