| Bloomsbury Circle Ltd. | Extraterritorial | 2016 |
| Bloomsbury EOT Limited | Administrative & support | 2022 |
| Blore Bowron Limited | Manufacturing | 1997 |
| Blou Properties Ltd | Real estate | 2023 |
| Blpsolutions Limited | Administrative & support | 2007 |
| BLU Turtle Limited | Professional & scientific | 2010 |
| Blue Candi LAB London Ltd | Agriculture & fishing | 2018 |
| Blue Collar Bournemouth Limited | Hospitality | 2025 |
| Blue Collar Group Ltd | Financial services | 2021 |
| Blue Collar Street Food Limited | Hospitality | 2016 |
| Blue Collar Ventures Ltd | Hospitality | 2021 |
| Blue Communication Limited | Information & communication | 2006 |
| Blue Cubed Holdings Limited | Financial services | 2022 |
| Blue Defence and Security Limited | Professional & scientific | 2012 |
| Blue Door Electrical Limited | Construction | 2019 |
| Blue Earth Diagnostics Limited | Professional & scientific | 2013 |
| Blue Earth Therapeutics Limited | Professional & scientific | 2021 |
| Blue Green Properties Limited | Construction | 2026 |
| Blue Heron Group Limited | Professional & scientific | 2020 |
| Blue Note Solutions Ltd | Professional & scientific | 2010 |
| Blue Pebble Consulting Ltd | Professional & scientific | 2016 |
| Blue Sapphire North Ltd | Administrative & support | 2025 |
| Blue Sky Mind Limited | Administrative & support | 2016 |
| Blue Triangle Limited | Wholesale & retail | 2023 |
| Blue Wired Limited | Professional & scientific | 2026 |
| Bluebell Legal Ltd | Professional & scientific | 2021 |
| Bluebrick Advisory Limited | Education | 2026 |
| Bluecape Consulting Limited | Administrative & support | 2019 |
| Blueleaf Oxford Ltd | Wholesale & retail | 2025 |
| Bluelec Ltd | Construction | 2024 |
| Bluelemur Consulting Limited | Professional & scientific | 2021 |
| Bluemecha Ltd | Information & communication | 2019 |
| Bluemont Arbor Partners Ltd | Information & communication | 2021 |
| Blueprints 3D Ltd | Manufacturing | 2024 |
| Blueviewcare Ltd | Health & social care | 2025 |
| BM Luxury Travel Ltd | Transport & logistics | 2026 |
| BM Selfless Care Ltd | Health & social care | 2022 |
| Bman Brewery Ltd | Manufacturing | 2021 |
| BMC Performance Limited | Information & communication | 2005 |
| BMC Ventures Limited | Professional & scientific | 2004 |
| Bmrb Engineering Ltd | Professional & scientific | 2022 |
| Bn&R Services Ltd | Administrative & support | 2026 |
| Boars Hill Motor Services Limited | Wholesale & retail | 2024 |
| Boateng & Mary UK Ltd | Education | 2018 |
| Boathouse Consortium Limited | Education | 1989 |
| Bodleian Homes Holdings Limited | Financial services | 2026 |
| Bodleian Homes Limited | Construction | 2024 |
| Bodrum Trading Ltd | Hospitality | 2022 |
| Body Mind & Soul 4 YOU Community Interest Company | Other services | 2023 |
| Bokeng Sons and Daughter Limited | Health & social care | 2023 |
| Bold Work Studios Limited | Information & communication | 2024 |
| Bolff Healthcare Services Ltd | Health & social care | 2018 |
| BON MOT Media Limited | Administrative & support | 2006 |
| Bonacon Capital Limited | Professional & scientific | 2016 |
| Bond Street (BP) Consulting Ltd | Professional & scientific | 2019 |
| Bongo IT Ltd | Information & communication | 2013 |
| Bonn Square News Ltd | Wholesale & retail | 2024 |
| Book Polishers Ltd | Information & communication | 2014 |
| Bookbank Limited | Wholesale & retail | 2011 |
| Bookkeeping Finance Limited | Professional & scientific | 2023 |
| Booksvp Ltd | Administrative & support | 2020 |
| Bookwhen Ltd | Information & communication | 2014 |
| Boomerang Properties Ltd | Real estate | 2019 |
| Boreham's Car Electrical Service Limited | Financial services | 1939 |
| Boreham's Holdings Limited | Professional & scientific | 2026 |
| Borjan Ltd | Transport & logistics | 2014 |
| Born of WAR Limited | Information & communication | 2009 |
| Bosch Carpentry Ltd | Construction | 2021 |
| Boshor Holdings Limited | Real estate | 2021 |
| Boss Barber Oxford Ltd | Other services | 2025 |
| Boss Chic Enterprise Ltd | Wholesale & retail | 2017 |
| Boss Fork Truck Training Limited | Transport & logistics | 1997 |
| Boss Property Group Ltd | Real estate | 2020 |
| Boss Shop Ltd | Wholesale & retail | 2024 |
| Boston Place Fertility Limited | Real estate | 2005 |
| Bota Properties Ltd | Real estate | 2025 |
| Bota Property Ltd | Real estate | 2025 |
| Bota Services Ltd | Transport & logistics | 2025 |
| Bota Taxis Ltd | Transport & logistics | 2025 |
| Botley Barbers Ltd | Other services | 2023 |
| Botley Booze Ltd | Wholesale & retail | 2026 |
| Botley Bridges | Health & social care | 2016 |
| Botley Executive Cars Ltd | Transport & logistics | 2021 |
| Botley Launderette Limited | Other services | 2021 |
| Bottlepr Limited | Administrative & support | 2003 |
| Boujee Homeware Ltd | Wholesale & retail | 2026 |
| Bounce Design Ltd | Professional & scientific | 2004 |
| Bounce Video Ltd | Information & communication | 2015 |
| Boundary Brook Community Projects CIC | Arts & recreation | 2024 |
| Bourton Vale Cricket Limited | Arts & recreation | 2026 |
| Boutique Hair & Beauty Summertown Limited | Other services | 2022 |
| Bovingdon Estates Ltd | Real estate | 2015 |
| BOW Software Limited | Information & communication | 2025 |
| Bowde Ltd | Professional & scientific | 2020 |
| Bowen International(Uk) Ltd | Wholesale & retail | 2025 |
| Bowery Resources Limited | Mining & quarrying | 2021 |
| Bowfell Energy Limited | Energy | 2018 |
| Bowman Stone Group Limited | Administrative & support | 2024 |
| Box of Clicks Ltd | Information & communication | 2009 |
| Box Productions Limited | Arts & recreation | 1986 |