| Blue Cedar Homes Management Company Limited | Households | 2010 |
| Blue Rock Business Services Ltd | Professional & scientific | 2002 |
| Blue TIN Produce Ltd | Wholesale & retail | 2014 |
| Bluemeringue Ltd | Administrative & support | 2017 |
| Bluestone HR Limited | Administrative & support | 2021 |
| Bluton Limited | Wholesale & retail | 2021 |
| Bmaine Limited | Financial services | 2021 |
| Botsandus Operations Ltd. | Professional & scientific | 2022 |
| Bottlesoc Ltd | Manufacturing | 2023 |
| Boxshop Services Limited | Other services | 1987 |
| Boxshop Services Trustees Limited | Professional & scientific | 2023 |
| BPC Target Sports CIC | Education | 2021 |
| Branching OUT Florists Limited | Wholesale & retail | 2009 |
| Brand Oxford Ltd | Professional & scientific | 2021 |
| Briarpath Properties Limited | Construction | 1992 |
| Bridge House Management (Wallingford) Limited | Households | 1994 |
| Bridget Fury Limited | Administrative & support | 2007 |
| Bright Advice Partnership Ltd | Professional & scientific | 2021 |
| Brightday Enterprises Limited | Manufacturing | 2002 |
| Brightfest Events Limited | Wholesale & retail | 2023 |
| Brightloom Ltd | Wholesale & retail | 2025 |
| Brightstone Ventures Limited | Professional & scientific | 2017 |
| Brightwell Builders Ltd | Construction | 2015 |
| Brightwell Garage (Brightwell) Limited | Wholesale & retail | 2017 |
| Brightwell Marquees Limited | Administrative & support | 2019 |
| Brightwell Medical Limited | Information & communication | 2026 |
| Bristow Consultants UK Limited | Real estate | 2015 |
| British Seagull Limited | Professional & scientific | 1999 |
| Brosland Limited | Real estate | 2017 |
| Btex Limited | Construction | 2017 |
| Buckaroo and Castles TOO Limited | Administrative & support | 2025 |
| Build Nine Group Ltd | Construction | 2023 |
| Build Nine Property Group Ltd | Construction | 2021 |
| Bunkfest | Arts & recreation | 2002 |
| Burling Investments Limited | Real estate | 2004 |
| Bushell Estate Limited | Real estate | 2016 |
| Business Risk Solutions Ltd | Professional & scientific | 1997 |
| Busy Brush Cafe Ltd | Arts & recreation | 2014 |
| Bygone Boating Ltd | Transport & logistics | 2016 |
| C & G Motors (Cholsey) Ltd | Wholesale & retail | 2025 |
| C S Film & Media Services Limited | Construction | 2014 |
| C V P (Oxford) Limited | Information & communication | 1999 |
| C. Putnam and Sons Ltd. | Construction | 2010 |
| Caister Marsden Ltd | Wholesale & retail | 2021 |
| Calea Regulatory Ltd | Professional & scientific | 2024 |
| Calleva Communications Limited | Professional & scientific | 2025 |
| Calleva Properties Limited | Real estate | 2024 |
| Calvitium Ltd | Financial services | 2019 |
| Camber Solutions Limited | Professional & scientific | 2026 |
| Camenlon Services Limited | Health & social care | 2018 |
| Camfield Construction Ltd | Construction | 2023 |
| Carmel Terrace Limited | Professional & scientific | 2002 |
| Carport Tech Ltd | Wholesale & retail | 2022 |
| Cashflow Advance Ltd | Administrative & support | 2020 |
| Castle Osteopathy Ltd | Health & social care | 2026 |
| CATCHCO2 Limited | Professional & scientific | 2022 |
| Cavendish Home Investments Limited | Real estate | 2022 |
| CB Advisory Ltd | Information & communication | 2012 |
| Celtegra Limited | Professional & scientific | 2005 |
| Centipede Construction Limited | Construction | 2012 |
| Cerebration Ltd | Information & communication | 2026 |
| Ceres Software Group Ltd | Administrative & support | 2025 |
| CG Tax & Accounting Services Limited | Other services | 2024 |
| Chaise Cottages Management Company Limited | Households | 2005 |
| Challenger Consultants Limited | Professional & scientific | 2025 |
| Chalmere Ltd | Information & communication | 2011 |
| Chancery Mews Residents Association Limited | Households | 1986 |
| Channel Green TV Limited | Information & communication | 2010 |
| Channelview Software Limited | Information & communication | 1992 |
| Chesil Construction Limited | Construction | 2019 |
| Chessman Developments Limited | Professional & scientific | 1987 |
| Childhood Matters Consulting Ltd | Education | 2022 |
| Childhood Matters Inclusion Services Ltd | Education | 2025 |
| Chiltern Connections Limited | Manufacturing | 1990 |
| Chiltern Seeds Limited | Wholesale & retail | 2012 |
| Cholsey & Wallingford Railway Preservation Society | Transport & logistics | 1985 |
| Cholsey and Wallingford Railway Limited | Transport & logistics | 2021 |
| Cholsey Cleaning Services Limited | Administrative & support | 2008 |
| Cholsey Information Security Limited | Information & communication | 2010 |
| Cholsey Primary Academy Trust | Education | 2013 |
| Cholsey Thai Limited | Hospitality | 2026 |
| Chris Butler Limited | Health & social care | 2015 |
| Chris Gurney Consulting Ltd | Hospitality | 2001 |
| Christopher Hardy & Co Limited | Professional & scientific | 2015 |
| Cielo Azul Ltd | Financial services | 2017 |
| Cilco Solutions Ltd | Information & communication | 2023 |
| Circuit Supplies International Limited | Wholesale & retail | 2005 |
| City & Suburban (Holdings) Limited | Financial services | 1991 |
| City and Suburban Properties Limited | Construction | 1987 |
| CJ Consultants - Payments Ltd | Professional & scientific | 2021 |
| Cjgardens Ltd | Real estate | 2015 |
| CJH Estates Limited | Administrative & support | 2016 |
| Claire Andersson Ltd | Hospitality | 2015 |
| Claire Morley Ltd | Construction | 2018 |
| Clarity Marketing Research Ltd | Professional & scientific | 2010 |
| Clarity Video Ltd | Information & communication | 2022 |
| Classic Road Trips Ltd | Arts & recreation | 2012 |
| Clayton Black Ltd | Administrative & support | 2024 |
| Clean Living Cleaning Ltd | Administrative & support | 2019 |
| Cleanat Limited | Administrative & support | 2026 |