| J T & J Stewart Limited | Wholesale & retail | 2003 |
| J T Parsons (Windermere) Limited | Extraterritorial | 1990 |
| J W Johnson & SON Ltd | Other services | 2002 |
| J. Brownell & SON Limited | Construction | 1973 |
| J. Little & SON Limited | Construction | 2003 |
| J. Perruzza & Sons Ltd | Hospitality | 2001 |
| J.A. Jones Ltd | Construction | 2003 |
| J.B. Banks & SON Limited | Wholesale & retail | 1933 |
| JA Properties (Cumbria) Ltd | Real estate | 2017 |
| Jacksons Timber Limited | Wholesale & retail | 1999 |
| Jade Tree Ltd | Hospitality | 2001 |
| James Cropper Converting Limited | Manufacturing | 2003 |
| James Cropper EBT Limited | Manufacturing | 2007 |
| James Cropper Paper Limited | Extraterritorial | 2004 |
| James Cropper Public Limited Company | Manufacturing | 1889 |
| James Cropper Speciality Papers Limited | Manufacturing | 2003 |
| James Johnson Building Limited | Construction | 2012 |
| Jamie Flynn Sound Recordist Limited | Information & communication | 2002 |
| Jamie Hardy Joinery Services Limited | Construction | 2002 |
| JB Restorations Ltd | Wholesale & retail | 2003 |
| JD Smith Design Ltd | Professional & scientific | 2019 |
| Jemma Gabriel Ltd | Construction | 2020 |
| JEMMA5 Limited | Construction | 2020 |
| Jewellery by Michael King Ltd | Manufacturing | 2006 |
| JH & J FOX Limited | Wholesale & retail | 2002 |
| John Bracken Ltd | Construction | 2001 |
| John Jordan Limited | Wholesale & retail | 1996 |
| John Richardson & SON (Timber Merchants) Limited | Wholesale & retail | 2004 |
| John Roberts Advertising Limited | | 1976 |
| John Sanderson Forestry Limited | Agriculture & fishing | 2002 |
| John W Carlisle Limited | Extraterritorial | 1998 |
| John Wilkinson QA Limited | Professional & scientific | 2007 |
| Johnston & Bulman Limited | Wholesale & retail | 1973 |
| Joseph Dunn (Building Contractor) Limited | Construction | 2003 |
| Julie Bell Consulting Limited | Professional & scientific | 2002 |
| K a & P J Woodman & SON Ltd | Agriculture & fishing | 2004 |
| K R Blinds Limited | Wholesale & retail | 2002 |
| K S Business Park Limited | Construction | 2007 |
| K W & B L Harrison Limited | Agriculture & fishing | 2006 |
| Kadcon Limited | Real estate | 2001 |
| Kankku (Group) Limited | Financial services | 2023 |
| KC Contract Flooring Limited | Construction | 2005 |
| Keith Thomas Motor Engineers Limited | Wholesale & retail | 2003 |
| Kelton Electrical Ltd. | Construction | 2003 |
| Kemvyl Services Ltd | Wholesale & retail | 2021 |
| Kendal Caravans Limited | Wholesale & retail | 1988 |
| Kendal Dental Care Limited | Health & social care | 2007 |
| Kendal Joinery Co. Limited | Real estate | 1964 |
| Kendal Masonic Hall Limited | Other services | 1996 |
| Kendal Metal Works Limited | Manufacturing | 1974 |
| Kent Valley Colour Printers Limited | Manufacturing | 1990 |
| Kepplewray Limited | Hospitality | 1992 |
| Keswick Bridge Limited | Real estate | 1992 |
| Keswick Football Club Limited | Arts & recreation | 2007 |
| Keswick Motor Company Limited | Wholesale & retail | 1963 |
| Keswick Plumbing and Heating Services Limited | Construction | 2002 |
| Kevin Kyte Construction Limited | Construction | 2008 |
| Key Learning and Leisure Ltd | Education | 2007 |
| Kilnstown Farms Limited | Agriculture & fishing | 2006 |
| Kingston Products Limited | Manufacturing | 1997 |
| Kirkaldy & ROE Ltd | Construction | 2006 |
| Kirkby Lonsdale Rugby Union Football Club (2017) Limited | Real estate | 2017 |
| KN Plumbing Heating and GAS Services Limited | Construction | 2024 |
| Knottallow Limited | Extraterritorial | 1987 |
| Kristian Limited | Construction | 2006 |
| Kroe Ltd | Information & communication | 2020 |
| Kutz (Barrow) Limited | Other services | 2002 |
| L Kassell Ltd | Financial services | 2018 |
| L.Hutton & Co.(Windermere)Limited | Wholesale & retail | 1937 |
| Lake District Boat Club Limited | Arts & recreation | 1973 |
| Lake District Holdings Limited | Financial services | 1987 |
| Lake District Hospitality Ltd | Extraterritorial | 2003 |
| Lake District Motor Museum Limited | Extraterritorial | 2007 |
| Lake District Places Limited | Hospitality | 2023 |
| Lake RAJ Property Ltd | Real estate | 2022 |
| Lakeland Apartments Ltd | Hospitality | 2023 |
| Lakeland Arts Enterprises Limited | Wholesale & retail | 1995 |
| Lakeland Arts Support Trust | Arts & recreation | 1998 |
| Lakeland Building Design Limited | Construction | 2002 |
| Lakeland Cleaning Solutions Ltd. | Administrative & support | 2006 |
| Lakeland Fells Furniture Limited | Manufacturing | 2004 |
| Lakeland FLY Tying Limited | Wholesale & retail | 2003 |
| Lakeland Green Slate & Stone Company Limited | Mining & quarrying | 1957 |
| Lakeland Health Ltd. | Extraterritorial | 2000 |
| Lakeland Instrumentation Limited | Administrative & support | 2007 |
| Lakeland Stadium Limited | Arts & recreation | 1963 |
| Lakeland Trucks Limited | Wholesale & retail | 1990 |
| Lakeside and Haverthwaite Railway Company Limited | Transport & logistics | 1970 |
| Lambkins Nursery Ltd | Education | 2012 |
| Lamont Pridmore (South Cumbria) Limited | Professional & scientific | 2005 |
| Lamont Pridmore Keswick Limited | Professional & scientific | 2003 |
| Landscroft Homes Limited | Construction | 1993 |
| Laurmar Limited | Manufacturing | 2003 |
| Lawncross Limited | Real estate | 2000 |
| LEE Bowron Glazing Ltd | Construction | 2003 |
| Leslie Cleeland Limited | Wholesale & retail | 1972 |
| Letpower Global Ltd | Professional & scientific | 2026 |
| Levens Farms Limited | Agriculture & fishing | 1986 |
| Lewthwaite Associates Limited | Professional & scientific | 2005 |
| Light & Salt Provisions CIC | Hospitality | 2026 |