| J O'Leary Ltd | Construction | 2020 |
| J P Burners Ltd | Manufacturing | 2003 |
| J P G Services Limited | Professional & scientific | 2002 |
| J V Painters Limited | Construction | 2002 |
| J. Hill Electrical Contractors Limited | Construction | 2005 |
| J. P. Springthorpe & Co. Limited | Other services | 2004 |
| J.C.P. Kitchens Limited | Construction | 2003 |
| J.S. Kyle Ltd | Construction | 2003 |
| Jacqui Clarke Limited | Administrative & support | 2005 |
| JAK Stationers Limited | Wholesale & retail | 1990 |
| Jalaram Estates Limited | Real estate | 2003 |
| Jalpur Global Investments Limited | Real estate | 2009 |
| James Sellicks Estate Agents Limited | Real estate | 2002 |
| Jamvick 2 Limited | Administrative & support | 2023 |
| Jamvick Ltd | Real estate | 2021 |
| Janerobcat Limited | Professional & scientific | 2004 |
| JAR Properties Ltd | Real estate | 2004 |
| JAS Property Solutions Limited | Real estate | 2017 |
| Jayclem Holding Company Limited | Professional & scientific | 1997 |
| Jazz Interiors Limited | Construction | 2003 |
| JB Fabrications (Europe) Limited | Manufacturing | 2003 |
| Jellybean Creative Limited | Professional & scientific | 2005 |
| Jelson Homes Limited | Construction | 1965 |
| JG Fabrications (Midlands) Limited | Manufacturing | 2003 |
| JIM Watts Signs Limited | Manufacturing | 2003 |
| JJ Burton Joinery Limited | Construction | 2007 |
| JMB Business Consultancy Limited | Professional & scientific | 2019 |
| John F. Milner (Bakers) Limited | Manufacturing | 1978 |
| John F. Mould & Co (Loughborough) | | 1991 |
| John Hall (Fertilisers) Limited | Manufacturing | 1959 |
| John Manship Records Ltd | Wholesale & retail | 2001 |
| John Paul & Sons Limited | Wholesale & retail | 1926 |
| John W.Hartley,Limited | Extraterritorial | 1932 |
| Jomac Original Ltd | Manufacturing | 2000 |
| Jonathan Firth Design Limited | Professional & scientific | 2003 |
| Jora Trading Limited | Extraterritorial | 2006 |
| Joseph Henry Ltd | Information & communication | 2017 |
| Joshi Associates Limited | Professional & scientific | 2003 |
| Josiah Hincks Limited | Administrative & support | 2000 |
| JRL Solutions Limited | Professional & scientific | 2006 |
| JS Joinery (UK) Ltd | Construction | 2003 |
| Judge Opticians Limited | Health & social care | 2005 |
| Just Rewards Ltd | Professional & scientific | 2008 |
| Just Solutions UK Limited | Manufacturing | 1995 |
| K a Mccole Limited | Professional & scientific | 2009 |
| K S Hicklin Limited | Extraterritorial | 2007 |
| K-Mitch Investments Limited | Wholesale & retail | 2006 |
| K.B. Elsmore & Sons Limited | Manufacturing | 1961 |
| K.M. Beesley (Construction Services) Ltd | Construction | 1983 |
| Kaimann (UK) Limited | Extraterritorial | 2015 |
| Kaliba Limited | Professional & scientific | 2008 |
| Kampala Gold Limited | Wholesale & retail | 2000 |
| Kane Campbell Nash Limited | Real estate | 2000 |
| Kasba Limited | Professional & scientific | 2004 |
| Kastor Limited | Professional & scientific | 1989 |
| Kate Shepherd Ltd | Other services | 2017 |
| Kaypee Construction Ltd | Construction | 2007 |
| KD Property Portfolio Limited | Real estate | 2023 |
| Kell (UK) Ltd | Manufacturing | 2005 |
| Kenmark Limited | Real estate | 2000 |
| Kettleby Foods Limited | Extraterritorial | 1998 |
| Key Locations Ltd. | Administrative & support | 2001 |
| Keycase Limited | | 2003 |
| KG Ventures Limited | Real estate | 2015 |
| KGN Heating LLP | | 2023 |
| Kiah Holdings Limited | Professional & scientific | 2006 |
| Kibworth 6 Ltd | Professional & scientific | 2002 |
| KID Properties Limited | Construction | 2006 |
| Kiki BAG. UK Ltd | Manufacturing | 1997 |
| Kilcruise Developments Limited | Real estate | 2003 |
| Kilworth Associates Ltd | Professional & scientific | 2004 |
| Kilworth Lakes Limited | Real estate | 2024 |
| Kilworth Springs Golf Club Limited | Other services | 1995 |
| Kindeva Drug Delivery Limited | Manufacturing | 2020 |
| King West Limited | Professional & scientific | 2000 |
| Kingfisher Marine Engineering Limited | Manufacturing | 1993 |
| Kingsbridge Property Solutions Limited | Construction | 2016 |
| Kingsbury Hall Developments Limited | Construction | 2003 |
| Kingsbury Hall Preservation Limited | Construction | 2003 |
| Kingsgate Health Limited | Manufacturing | 2008 |
| Kitchen Creations (Leicester) Ltd | Professional & scientific | 2004 |
| Kite Jewellery Limited | Manufacturing | 1985 |
| Kivi Properties Limited | Real estate | 2021 |
| Kiwi Property Services Ltd | Other services | 2007 |
| Klingman Scott Limited | Wholesale & retail | 1989 |
| Knightsbridge Investments & Asset Management Limited | Real estate | 1999 |
| Knowles Clothing Ltd | Wholesale & retail | 2026 |
| Known Leicester Limited | Other services | 2019 |
| KSB Limited | Wholesale & retail | 1923 |
| Kubus Design Ltd | Professional & scientific | 2003 |
| Kuku's Fabrics Limited | Manufacturing | 2004 |
| L & F Plastering Contractors Limited | Construction | 2019 |
| L a Sturgess Limited | Professional & scientific | 2005 |
| L M Van Moppes & Sons Diamond Tools Limited | Extraterritorial | 1947 |
| L. J. Electrical of Loughborough Ltd | Construction | 2005 |
| L.A. Creations Ltd | | 2004 |
| L.E. Jackson (Coachworks) Limited | Manufacturing | 1945 |
| L.M. Liveries LLP | | 2006 |
| LA Nail & Beauty Spa Ltd | Other services | 2019 |
| LAC Truckin Services Limited | Transport & logistics | 2021 |