| John Sutherland Haulage Ltd | Transport & logistics | 2018 |
| John Szwec Consulting Limited | Administrative & support | 2013 |
| John Vaughan Limited | Professional & scientific | 2004 |
| Johnsh Consultancy Ltd | Professional & scientific | 2022 |
| Johnson Building Services Ltd | Construction | 2020 |
| Johnson Supply & Storage Limited | Other services | 2019 |
| Johnsons Builders Limited | Construction | 2015 |
| Joint Replacement Ltd | Health & social care | 2024 |
| Jollyseb Ltd | Health & social care | 2024 |
| JON Greiff Ltd | Other services | 2015 |
| Jonathan Edgar Boat Holidays Ltd | Hospitality | 2021 |
| Jonck Ltd | Other services | 2016 |
| Jones the Hand Limited | Health & social care | 2023 |
| Joseph Morris Butchers Limited | Wholesale & retail | 2011 |
| Joy Strategy Ltd | Professional & scientific | 2025 |
| JP Electrical (Midlands) Ltd | Construction | 2026 |
| JRZ Arcade Ltd | Arts & recreation | 2026 |
| JS Whitewalling Limited | Construction | 2023 |
| JT8 Forestry Limited | Agriculture & fishing | 2006 |
| Julia Baron Limited | Other services | 2013 |
| Julian Cowie Architects Limited | Professional & scientific | 1997 |
| Julie Smith Consultancy Ltd | Real estate | 2007 |
| Julie Trans & Services Ltd | Construction | 2017 |
| July & MAE Limited | Wholesale & retail | 2021 |
| Junction 20 Pallets Ltd | Manufacturing | 2018 |
| Jupiter Industries Limited | Professional & scientific | 1992 |
| Just Enough Consulting Ltd | Information & communication | 2020 |
| Just Jigsaws Ltd. | Manufacturing | 1996 |
| Just Life Ltd | Financial services | 2025 |
| Just SAY Beer Limited | Real estate | 1999 |
| Just VAT Limited | Professional & scientific | 2014 |
| Juxta Design (Midlands) Limited | Professional & scientific | 2020 |
| Juxta Limited | Construction | 2021 |
| JW Enterprises Limited | Extraterritorial | 2013 |
| JW Landscaping and Design Limited | Administrative & support | 2020 |
| K & D Medical Limited | Other services | 2012 |
| K Consulting Limited | Construction | 1996 |
| K Makam Ltd | Real estate | 2015 |
| K&E Irons Plumbing Services Ltd | Construction | 2022 |
| KAI Beachwear Ltd | Extraterritorial | 2012 |
| Kalium Ltd | Wholesale & retail | 2017 |
| Kanu Achinivu Limited | Other services | 2013 |
| Kanu Achinivu Properties Limited | Real estate | 2019 |
| Karim MNP Limited | Wholesale & retail | 2025 |
| Kars-Leicestershire Ltd | Wholesale & retail | 2024 |
| KBS Installations Ltd | Other services | 2018 |
| KCD Surveyors Ltd | Wholesale & retail | 2020 |
| Kcsh Properties Ltd | Real estate | 2015 |
| KD Events Ltd | Arts & recreation | 2024 |
| KD Lewis Maintenance Services Ltd | Manufacturing | 2024 |
| Keith's Hair Studio Limited | Arts & recreation | 2006 |
| Kelco Country Ltd | Wholesale & retail | 2025 |
| Kemsam Consultancy Solutions Limited | Hospitality | 2024 |
| Kenstech Ltd | Extraterritorial | 2018 |
| Kent EYE Services Ltd | Health & social care | 2024 |
| KER Commercial Ltd | Extraterritorial | 2016 |
| Kerato Vision Ltd | Health & social care | 2019 |
| Ketteridge Holdings Ltd | Financial services | 2023 |
| Keyshel Holdings Limited | Professional & scientific | 2019 |
| Keyshel Interiors (04) Limited | Construction | 2004 |
| Keyshel Properties Limited | Real estate | 2019 |
| Keystone PMO Ltd | Professional & scientific | 2026 |
| KHW Pharma Consultancy Limited | Professional & scientific | 2021 |
| Kibworth Business Park Management Company Limited | Real estate | 2016 |
| Kidney Failure Risk Ltd | Education | 2023 |
| Kilworth Accountancy Limited | Professional & scientific | 2006 |
| Kilworth Consultants Limited | Extraterritorial | 2024 |
| Kilworth Developments Limited | Construction | 2024 |
| Kilworth Farms Limited | Agriculture & fishing | 1965 |
| Kilworth Grange Management Services Ltd | Professional & scientific | 2018 |
| Kilworth Properties Limited | Real estate | 2015 |
| Kilworth Window Cleaning Limited | Administrative & support | 2023 |
| Kim’S Coffee Ltd. | Hospitality | 2022 |
| Kingsgate Lettings Ltd | Financial services | 2013 |
| Kingsmead Marquees Limited | Manufacturing | 1998 |
| Kingsthorpe Upper Crust Catering Service Limited | Hospitality | 1991 |
| KIO Developments Ltd | Construction | 2018 |
| KIO Properties Limited | Real estate | 2018 |
| KIO Stays Limited | Real estate | 2023 |
| Kirkstone Land and Property Development Limited | Financial services | 2026 |
| Kitchen Box Trailer Hire Ltd | Other services | 2025 |
| Kitreni Ltd | Information & communication | 2001 |
| Kjld Consultancy Limited | Professional & scientific | 2015 |
| KLH Ventures LLP | | 2025 |
| KLT Utility Services Ltd | Construction | 2021 |
| KNH Scaffolding Ltd | Construction | 2022 |
| Knights Medical Ltd. | Health & social care | 2020 |
| KNP Group Ltd | Wholesale & retail | 2017 |
| Kobe UK Limited | Wholesale & retail | 1995 |
| Koeks Ltd | Wholesale & retail | 2024 |
| Kphr Solutions Limited | Administrative & support | 2015 |
| KR Estates (Leicester) Ltd | Other services | 2017 |
| Krishdev Consultants Ltd | Information & communication | 2026 |
| Kronstadt Transport Ltd | Transport & logistics | 2024 |
| KS Construct (UK) Ltd | Construction | 2025 |
| Kural Ltd | Real estate | 2019 |
| Kustos Collection Ltd | Other services | 2026 |
| Kutchenhaus Lutterworth Ltd | Construction | 2022 |
| KXR Medical Ltd | Health & social care | 2022 |
| L & B Leisure Limited | | 1984 |