| Kanla Ltd | Real estate | 2023 |
| Kanndo Limited | Financial services | 2022 |
| Kanndo Property Services Limited | Professional & scientific | 2013 |
| Karatedo Design Limited | Manufacturing | 2024 |
| Karden Limited | Hospitality | 2025 |
| Kardos Car & Commercial Services Ltd | Wholesale & retail | 2019 |
| Karl Moore Construction Limited | Construction | 2004 |
| Kate Bradley Gardens Limited | Administrative & support | 2022 |
| Kate Lloyd Morgan Therapy Limited | Health & social care | 2020 |
| Kate Perry Limited | Professional & scientific | 2023 |
| Kayn Solutions Limited | Information & communication | 2022 |
| KC Autocolours Limited | Wholesale & retail | 2004 |
| Kclh Limited | Real estate | 2012 |
| KD Design (Oxford) Ltd | Professional & scientific | 2014 |
| KDI Consulting Limited | Professional & scientific | 2013 |
| Keeley Ltd | Professional & scientific | 2020 |
| Keevill Heritage Ltd | Other services | 2011 |
| Kelston Rise Management Company Limited | Households | 2004 |
| Keltbray Fleet Limited | Administrative & support | 2023 |
| Kelu PUB Company Ltd | Hospitality | 2019 |
| Kemp Garden Design Ltd | Professional & scientific | 2023 |
| Kenby Limited | Information & communication | 2008 |
| Kentixen Engineering Limited | Wholesale & retail | 2021 |
| Kerala Food Factory UK Ltd | Hospitality | 2025 |
| Kesan Limited | Hospitality | 2009 |
| Ketzaal Ltd | Health & social care | 2019 |
| Kevin Savill Consultancy Ltd | Professional & scientific | 2019 |
| Key Financial Solutions Limited | Financial services | 2010 |
| Keyani Aesthetics & Beauty Ltd | Other services | 2024 |
| Keybridge Developments Limited | Real estate | 2015 |
| Keybridge Property Limited | Real estate | 2025 |
| Keyes Precision Engineering Ltd | Manufacturing | 2025 |
| KFL Resourcing Ltd | Information & communication | 2020 |
| KGP Properties Limited | Real estate | 2014 |
| Khalti Private Limited | Hospitality | 2024 |
| Kheiron School of English Limited | Education | 2006 |
| Khush Ingredients Limited | Wholesale & retail | 2008 |
| Kidlington Management Limited | Real estate | 2006 |
| Kidlington NO2 LLP | | 2013 |
| Kidmore K9S Ltd | Other services | 2022 |
| Kier Homes Ltd | Real estate | 2024 |
| Kier Investment Group Ltd | Financial services | 2023 |
| Kilinjiro Trading Ltd | Financial services | 2022 |
| King Marketing Consultancy Limited | Professional & scientific | 2005 |
| Kingdom Design & Build Ltd | Construction | 2023 |
| Kingdom Pools Limited | Manufacturing | 2025 |
| Kingfisher Court (Woodstock) Residents Company Limited | Households | 1990 |
| Kingfisher Studios and Gallery Ltd | Arts & recreation | 2025 |
| Kingsley Cars Ltd | Wholesale & retail | 2012 |
| Kingsley Property Investments UK Limited | Real estate | 2020 |
| Kingsley Re-Fuel Ltd | Hospitality | 2022 |
| Kingston and Richmond Radiology Ltd | Professional & scientific | 2024 |
| Kingston Bagpuize Limited | Construction | 2017 |
| Kingswell International Limited | Professional & scientific | 1999 |
| Kingswell Justice Limited | Professional & scientific | 2019 |
| Kingswood Interiors Limited | Administrative & support | 1994 |
| Kirthall Ltd | Professional & scientific | 2004 |
| Kiss Kitchens & Doors Witney Ltd | Professional & scientific | 2026 |
| Kitchen in the Corner Limited | Wholesale & retail | 2018 |
| KJH Group Ltd | Professional & scientific | 2012 |
| KJR360 Support Ltd | Professional & scientific | 2025 |
| KL Preeminent Care Limited | Extraterritorial | 2020 |
| Klaen Health Ltd | Energy | 2025 |
| Klaen Holdings Limited | Financial services | 2024 |
| Klaen Limited | Manufacturing | 2023 |
| Kleenze Limited | Other services | 2017 |
| Kleera Ltd | Information & communication | 2024 |
| KLL Enterprises Ltd | Hospitality | 2025 |
| KLM Scaffolding Limited | Construction | 2023 |
| KMB Facilities Ltd | Information & communication | 2026 |
| KMS Construction Management Ltd | Construction | 2026 |
| Knez Limited | Health & social care | 2015 |
| KNF Neuberger U.K. Limited | Manufacturing | 1978 |
| Knox-Ev Limited | Professional & scientific | 2024 |
| Koala IT Ltd | Information & communication | 2016 |
| Kobalt Accounting Ltd | Professional & scientific | 2022 |
| Kohera Limited | Information & communication | 2004 |
| Kontempo Hair Design Ltd | Other services | 2022 |
| Korto Limited | Hospitality | 2018 |
| Koster Contractors Ltd | Agriculture & fishing | 2024 |
| KP Stone Care Ltd | Administrative & support | 2026 |
| KPM Interiors Ltd | Other services | 2004 |
| Krayma Technical Solutions Ltd | Information & communication | 2011 |
| Kriss Kross Hair & Beauty Ltd | Other services | 2008 |
| Kriston Technology Limited | Information & communication | 1998 |
| KSY Group Limited | Construction | 2026 |
| Kudos IT Solutions Ltd | Information & communication | 2012 |
| Kuester Design Ltd | Professional & scientific | 2020 |
| Kulture Talent Ltd | Professional & scientific | 2023 |
| Kunjamis Limited | Health & social care | 2025 |
| Kurba Limited | Hospitality | 2025 |
| Kutana Limited | Information & communication | 1997 |
| KV Investment Holdings Ltd | Financial services | 2022 |
| KYE Studios Ltd | Arts & recreation | 2020 |
| Kynetiq Automotive Ltd | Manufacturing | 2026 |
| L & R Carpets & Flooring Ltd | Construction | 2021 |
| L Harris Limited | Extraterritorial | 2024 |
| L.A. Perfection Limited | Other services | 2015 |
| LA PAZ Films Limited | Information & communication | 2016 |
| LA Torre Global Ltd | Wholesale & retail | 2021 |