| Jsailbrand Limited | Professional & scientific | 2021 |
| JSB Training Limited | Education | 2012 |
| JSL Property Limited | Real estate | 2015 |
| JSM Binning Limited | Real estate | 2020 |
| JSP Planning Limited | Professional & scientific | 2016 |
| JSW Consultants Limited | Professional & scientific | 2003 |
| JTS Estates Limited | Real estate | 2016 |
| Jubilee - Leamington | Education | 2013 |
| Julian Burton Ltd | Professional & scientific | 2025 |
| Julian Mynott Limited | Wholesale & retail | 2009 |
| Julian Rowe Transport Services Limited | Transport & logistics | 2019 |
| Julie Fenton Limited | Real estate | 2018 |
| Julvic Limited | Wholesale & retail | 2025 |
| Jumbo Deals Ltd | Wholesale & retail | 2025 |
| Junttan UK Operations Limited | Wholesale & retail | 2021 |
| Jurek Talents Ltd | Administrative & support | 2019 |
| Just 4 Walls Ltd | Construction | 2024 |
| Just Nice Clean Cars Limited | Wholesale & retail | 2010 |
| JW Law Limited | Professional & scientific | 2009 |
| JX Enterprises Ltd | Financial services | 2023 |
| JZ Aesthetics Ltd | Health & social care | 2022 |
| K Cleal Plumbing & Heating Ltd | Construction | 2018 |
| K G Brooks Electrical Ltd | Construction | 2018 |
| K S Music Company Limited | Manufacturing | 1985 |
| K&P Services Limited | Health & social care | 2024 |
| K9-TIME Limited | Other services | 2017 |
| Kaburia Legal Limited | Professional & scientific | 2012 |
| Kadcom Limited | Information & communication | 2016 |
| Kala and Raya 2.0 Limited | Real estate | 2023 |
| Kala and Raya Limited | Arts & recreation | 2022 |
| Kaleidoscope Press Limited | Manufacturing | 1993 |
| Kallin Consulting Limited | Professional & scientific | 2025 |
| Kamjant Project Services Ltd | Professional & scientific | 2026 |
| Kane Groundworks & Landscapes Ltd | Construction | 2026 |
| Kang Legacy Limited | Real estate | 2025 |
| Kangen Centre Leamington Spa Limited | Wholesale & retail | 2020 |
| Kansal Associates Limited | Hospitality | 2017 |
| Kanwar Rentals Ltd | Real estate | 2021 |
| Karen Delahunty Limited | Wholesale & retail | 2013 |
| Katana Ltd | Wholesale & retail | 2012 |
| Kate Clarke Consulting Ltd | Professional & scientific | 2023 |
| Kate Doxey Hair Limited | Other services | 2021 |
| Kathuria Photography Limited | Professional & scientific | 2025 |
| Kathy Leahy Limited | Professional & scientific | 2010 |
| Katie Alice Limited | Wholesale & retail | 2011 |
| Katie Dear Ltd | Manufacturing | 2022 |
| Katie Haircare Limited | Other services | 2023 |
| Katie LOU Events Ltd | Professional & scientific | 2018 |
| KBM UK Consultants Ltd | Information & communication | 2023 |
| KCG Enterprises Ltd | Agriculture & fishing | 2013 |
| KCG Operations Consultancy Limited | Professional & scientific | 2026 |
| KCM Design Ltd | Professional & scientific | 2020 |
| KCS Civil Engineering Limited | Construction | 2024 |
| Keefer Ltd | Construction | 2007 |
| Keem Healthcare Ltd | Health & social care | 2021 |
| Keen to BE Lean Ltd | Health & social care | 2013 |
| Keilia Holdings Ltd | Financial services | 2025 |
| Kelian Limited | Hospitality | 2019 |
| Kelly & Shackleton Ltd | Real estate | 2020 |
| Ketchell Holdings Ltd | Administrative & support | 2018 |
| Keto Software Ltd | Information & communication | 2010 |
| Ketsoc Developments Ltd | Construction | 2025 |
| KEY2ENABLE Assistive Technology Ltd | Information & communication | 2020 |
| Keynotes Technologies Ltd | Arts & recreation | 2021 |
| KF City & East Limited | Real estate | 2026 |
| Kfactory Limited | Information & communication | 2024 |
| KGD Construction Ltd | Construction | 2017 |
| KH Linus Limited | Real estate | 2023 |
| KH8 Limited | Real estate | 2013 |
| Khem in UK Limited | Information & communication | 2020 |
| Khessairi Ltd | Professional & scientific | 2018 |
| KHS Europe Limited | Extraterritorial | 2004 |
| Khyron Health Limited | Health & social care | 2009 |
| Kicks and Lace Ltd | Wholesale & retail | 2025 |
| Kiddies Korner Limited | Education | 2003 |
| Kidz Own OUT of School Club Limited | Education | 2008 |
| Kigass Aero Components Limited | Manufacturing | 1972 |
| Kigass Manufacturing Holdings Limited | Professional & scientific | 2021 |
| Kihaco Ltd | Professional & scientific | 2015 |
| Killowen Computers Repair Ltd | Other services | 2024 |
| Kindled Spirit | Other services | 2013 |
| Kindred Entertainment Digital Limited | Professional & scientific | 2004 |
| Kineton Chippy Limited | Hospitality | 2020 |
| Kineton Ltd | Extraterritorial | 2019 |
| Kineton Medical Services Ltd | Health & social care | 2020 |
| Kineton Mews Management Company Limited | Households | 2017 |
| Kineton Pizza Junction Ltd | Hospitality | 2021 |
| Kineton Playgroup Ltd | Education | 2006 |
| King's Acre Residents Association Limited | Households | 2000 |
| Kingston Cattery Ltd. | Hospitality | 2018 |
| Kingston Construction Limited | Construction | 2017 |
| Kingston Holt Farm Construction Ltd | Construction | 2024 |
| Kingswood Investors | Professional & scientific | 2011 |
| Kington Grove (Kineton) Management Company Limited | Households | 2020 |
| Kinzed Ltd | Information & communication | 2025 |
| Kirkham Farms (Warwick) Limited | Agriculture & fishing | 1991 |
| Kitchen and Bath Solutions Ltd | Construction | 2019 |
| Kitea Limited | Information & communication | 2018 |
| Kiwi Beauty Limited | Other services | 2007 |
| Kixx Coventry Ltd | Arts & recreation | 2021 |