| Center Stone Limited | Administrative & support | 2004 |
| Central Heat Pumps Limited | Professional & scientific | 1997 |
| Centre for Myth Cosmology and the Sacred Ltd | Education | 2020 |
| Centurian Soft Drinks Ltd | Wholesale & retail | 2010 |
| Cepacs Construction Limited | Construction | 2012 |
| Cepacs Homes Ltd | Real estate | 2014 |
| Certification International Limited | Professional & scientific | 1995 |
| Certified Plumbers Ltd | Construction | 2025 |
| CET Project Management Ltd | Professional & scientific | 2025 |
| CF Accountants Limited | Professional & scientific | 2005 |
| Cfna Limited | Administrative & support | 2016 |
| Cgsj Oxford Limited | Professional & scientific | 2017 |
| Chalice Consultancy Limited | Information & communication | 2000 |
| Chamlet Developments Ltd | Real estate | 2025 |
| Champden’S Property Ltd | Real estate | 2020 |
| Changemaker ISL Limited | Education | 2010 |
| Channel Mcgilchrist Limited | Administrative & support | 2021 |
| Channel View Farms Limited | Real estate | 2025 |
| CHAPTER92 Ltd | Wholesale & retail | 2025 |
| Chartinghall Holdings Limited | Health & social care | 2024 |
| Chaucer Bicester Industrial Estate Management Limited | Real estate | 1988 |
| Check Li-Ion Ltd | Manufacturing | 2021 |
| Cheeky Cheesecakes Ltd | Manufacturing | 2010 |
| Cheesybone Ltd | Wholesale & retail | 2021 |
| Chef Flavours Limited | Hospitality | 2016 |
| Cherete Limited | Construction | 2014 |
| Cherished Cheri Limited | Wholesale & retail | 2024 |
| Cherry Load Ltd | Transport & logistics | 2011 |
| Cherry Property Holdings Ltd | Real estate | 2016 |
| Cherry Store Ltd | Transport & logistics | 2013 |
| Cherry Tree Lane Property Ltd | Real estate | 2023 |
| Cherville Limited | Professional & scientific | 2017 |
| Cheshire Glow Clinic Ltd | Other services | 2023 |
| Chess Business Consulting Limited | Professional & scientific | 2017 |
| Chesters & Sons Limited | Construction | 2017 |
| Chesterton Management Limited | Households | 2006 |
| Chesterton Playgroup | Education | 2013 |
| Chettiar Education Ltd | Education | 2025 |
| Chic Aesthetic Limited | Other services | 2023 |
| Chicks and Sticks Ltd | Wholesale & retail | 2025 |
| Child Brain Injury Rehabilitation Services Limited | Other services | 2018 |
| Child Brain Injury Trust | Information & communication | 2006 |
| Children Charity Fund | Professional & scientific | 2010 |
| Chill Hair Products Ltd | Wholesale & retail | 2016 |
| Chilswell Management Services Limited | Administrative & support | 1963 |
| Chiltern Forest Golf Club 2018 Limited | Arts & recreation | 2018 |
| Chiltern Forest Golf Club Trading Limited | Arts & recreation | 2018 |
| Chiltern Forest School Ltd | Education | 2014 |
| Chiltern Leisure Limited | Wholesale & retail | 2008 |
| China Hand Limited | Extraterritorial | 1997 |
| Chinfum Limited | Hospitality | 2024 |
| Chipping Norton Dental Practice Limited | Health & social care | 2007 |
| Chloe's Antique Ltd | Wholesale & retail | 2015 |
| Chocology Limited | Wholesale & retail | 2001 |
| Chris and Doris Limited | Real estate | 2008 |
| Chris Lewis Group Limited | Construction | 2011 |
| Chris Weston Limited | Information & communication | 2012 |
| Chrisodel Holdings Ltd | Construction | 2026 |
| Chrisrad Limited | Health & social care | 2015 |
| Christians in Sport | Other services | 2001 |
| Christina White Ltd | Information & communication | 2025 |
| Christine Homes Holdings Limited | Real estate | 2018 |
| Christine Homes Limited | Construction | 2007 |
| Christine Homes Oxford Limited | Construction | 2017 |
| Chriswellaz Limited | Health & social care | 2018 |
| Chromakey-Hire Ltd | Manufacturing | 2013 |
| Church International Consulting Limited | Professional & scientific | 2010 |
| Church Lane (UK) Limited | Real estate | 2013 |
| Churchill Management & Consulting Services Ltd | Real estate | 2021 |
| Ciancy Construction & Property Ltd | Construction | 2020 |
| Cielt Ltd | Professional & scientific | 2018 |
| Cilingir Limited | Health & social care | 2023 |
| Cinch Telecoms Ltd | Information & communication | 2019 |
| Cinclus Limited | Public administration | 2012 |
| Cinis One Limited | Households | 2015 |
| Cirrus 1 Ltd | Information & communication | 2012 |
| Cirrus North Ltd | Information & communication | 2026 |
| Citron Tree Trading Ltd | Wholesale & retail | 2023 |
| Civicpath Ltd | Construction | 2025 |
| CJ Gutter Maintenance and Drainage Ltd | Water & waste | 2025 |
| CJM Cleans Limited | Administrative & support | 2024 |
| CJR Direct Ltd | Wholesale & retail | 2025 |
| Claimsite Property Management Limited | Households | 1987 |
| Clarissa’S Home Healthcare Services Ltd | Public administration | 2022 |
| Clarity Solutions Ltd | Information & communication | 2009 |
| Clark Properties (Bicester) Limited | Real estate | 2025 |
| Clasc Holdings Ltd | Financial services | 2025 |
| Classic Oils Limited | Extraterritorial | 2022 |
| Classic Trimworks Ltd | Wholesale & retail | 2017 |
| Classic Water Softeners Limited | Construction | 2022 |
| Claudia LUX Ltd | Wholesale & retail | 2026 |
| Clavis Marketing Limited | Professional & scientific | 2013 |
| CLC Consult Ltd | Professional & scientific | 2023 |
| Clean Crops Farm Limited | Manufacturing | 2025 |
| Clean Energon LP | | 2016 |
| Cleaning Management Ltd | Administrative & support | 2022 |
| Clear Skies Training Limited | Education | 2024 |
| Clear the Chaos Ltd | Other services | 2023 |
| Clearpath Estate Limited | Wholesale & retail | 2016 |
| Clemens Kueppers Holding Ltd | Financial services | 2021 |