| Bell Steel Fabrications Limited | Manufacturing | 1997 |
| Bella Mclean Design Ltd | Professional & scientific | 2024 |
| Bells and Whistles Behaviour Ltd | Education | 2018 |
| Beltus Limited | Financial services | 2025 |
| Benedict Campbell Limited | Professional & scientific | 2010 |
| Bennett Lettings Limited | Real estate | 1973 |
| Beretta Development Limited | Construction | 2017 |
| Bern-Art Ltd | Real estate | 2026 |
| Bernard & Company (Witney) Limited | Professional & scientific | 2002 |
| Berry Carpentry Ltd | Manufacturing | 2022 |
| Beside Bowie Ltd | Information & communication | 2014 |
| Bespoke Cover Solutions Ltd | Manufacturing | 2024 |
| Bespokemon Limited | Other services | 2020 |
| Best Company in UK Ltd | Construction | 2024 |
| Bestworth Limited | Wholesale & retail | 2003 |
| Better Informed Ltd | Professional & scientific | 2019 |
| Beyond Hills Limited | Real estate | 2020 |
| Beyond Your Brand Limited | Information & communication | 2018 |
| Bf-Led Ltd | Construction | 2018 |
| Bianca Elgar Limited | Manufacturing | 2012 |
| Bibby Rumbelow Limited | Education | 2008 |
| Bibi Property Limited | Real estate | 2022 |
| Bibo Limited | Manufacturing | 2006 |
| Bibury Courtyard Cottage Ltd | Hospitality | 2023 |
| Bicester Court (Kidlington) Management Company Limited | Households | 1976 |
| Bicester Investment Group Ltd | Real estate | 2025 |
| Bicester Pizza Limited | Hospitality | 2023 |
| BID Science Limited | Professional & scientific | 2010 |
| Big Mxworld Limited | Wholesale & retail | 2023 |
| Big Sunshine Books Limited | Information & communication | 2014 |
| Big Van World Holdings Limited | Financial services | 2023 |
| Big Van World Limited | Wholesale & retail | 2001 |
| Big Van World Marine Operations LLP | | 2024 |
| Big Van World Property Limited | Households | 2023 |
| Bigger Than Life Ltd | Other services | 2019 |
| Billiards UK Ltd | Manufacturing | 2018 |
| Bint Racing Ltd | Wholesale & retail | 2025 |
| Bint Support Services Ltd | Wholesale & retail | 2019 |
| Biolauncher Limited | Professional & scientific | 2001 |
| Biro Brick and Stonework Ltd | Construction | 2019 |
| Bishop & Sons Construction (Witney) Limited | Construction | 2015 |
| Bishop Property Holdings Limited | Real estate | 2026 |
| Bishops Place Management Company Limited | Households | 1994 |
| Biskitos Ltd | Wholesale & retail | 2012 |
| Bitwise IP Limited | Professional & scientific | 2024 |
| BJ Whitmarsh Ltd | Administrative & support | 2023 |
| BJA Executive Ltd | Wholesale & retail | 2024 |
| BJP Equestrian & Building Construction Ltd | Construction | 2022 |
| BL Consultancy Oxford Limited | Professional & scientific | 2014 |
| Black and Green Builders Ltd | Construction | 2024 |
| Black Dwarf Lightmoor Publications Limited | Information & communication | 2005 |
| Black Edge Services Ltd | Professional & scientific | 2020 |
| Blade Capital Limited | Financial services | 2018 |
| Bladon Leadership Limited | Professional & scientific | 2007 |
| Blake Bijoux Ltd | Manufacturing | 2024 |
| Blakeley Fitted Kitchens & Bathrooms Ltd | Construction | 2011 |
| Blakes Roofing Ltd. | Construction | 2021 |
| Blankstones Farm Management Company Limited | Households | 2011 |
| Blantyre Associates Ltd | Real estate | 2026 |
| Blenheim Court Residents Company (Woodstock) Limited | Households | 1983 |
| Blenheim Heights Management Company Limited | Households | 2013 |
| Blenheim Place (Witney) Management Company Ltd | Households | 2015 |
| Blessed Care 247 Ltd | Health & social care | 2019 |
| Blewbury Riding & Training Centre Limited | Arts & recreation | 1985 |
| Blewitt Court Residents Association Ltd | Households | 1999 |
| Bloom Bells Limited | Wholesale & retail | 2021 |
| Bloom Media Limited | Professional & scientific | 2012 |
| Bloomin' Amazing Limited | Wholesale & retail | 1990 |
| BLT Recruitment Holdings Limited | Professional & scientific | 2020 |
| Blue & Bear Ltd | Manufacturing | 2026 |
| Blue & Green Marine Commercial Solutions Limited | Manufacturing | 2009 |
| Blue and Yellow CUP CIC | Professional & scientific | 2024 |
| Blue Connecting Ltd | Health & social care | 2023 |
| Blue DOT Services Limited | Professional & scientific | 2021 |
| Blue GLO Limited | Construction | 2016 |
| Blue Meadow Home Care Ltd | Health & social care | 2026 |
| Blue South International Limited | Wholesale & retail | 2022 |
| Blue TAP Solutions Ltd | Water & waste | 2021 |
| Blue Water Films Limited | Information & communication | 2012 |
| BLUE42 LLP | | 2019 |
| Bluebell Gardens (Park Road) Management Company Limited | Households | 2020 |
| Bluedale Corporate Limited | Professional & scientific | 1980 |
| Bluedale Minerals PLC | Administrative & support | 2000 |
| Blueglo Servicing and Maintenance Ltd | Construction | 2019 |
| Blueground Ventures Ltd | Professional & scientific | 2013 |
| Blueline Solutions Ltd | Other services | 2012 |
| Bluepark Solutions Limited | Information & communication | 2004 |
| Blueprint Imaging Limited | Manufacturing | 2002 |
| BM Energi Ltd | Construction | 2025 |
| Bmex Limited | Wholesale & retail | 2000 |
| Bmjp Ltd | Real estate | 2024 |
| Board Dragon Ltd | Wholesale & retail | 2022 |
| Boddington Management Limited | Households | 2016 |
| Bodydamagequote Limited | Professional & scientific | 2019 |
| Boketto Bidco Limited | Administrative & support | 2015 |
| Boketto Holdco Limited | Administrative & support | 2015 |
| Boketto Midco 2 Limited | Administrative & support | 2020 |
| Boketto Midco 3 Limited | Administrative & support | 2021 |
| Boketto Midco Limited | Administrative & support | 2015 |
| Boketto Newco Limited | Administrative & support | 2015 |