| Johnstone Property Rentals Ltd. | Real estate | 2016 |
| Jolly Sailor Brewery Limited | Manufacturing | 2017 |
| Jonathan Myers Lighting Design Ltd | Administrative & support | 2021 |
| Jones Brothers Houses Ltd | Hospitality | 2025 |
| Joseph Hillary Limited | Extraterritorial | 1952 |
| JPG Competition Services Ltd | Wholesale & retail | 2025 |
| JR Design Services Limited | Professional & scientific | 2015 |
| K & R Haulage Ltd | Transport & logistics | 2018 |
| K H Twentyman Limited | Agriculture & fishing | 2008 |
| K Storr Agri Limited | Agriculture & fishing | 2023 |
| KCM Innovations Ltd | Wholesale & retail | 2024 |
| Keith EC Ltd | Manufacturing | 2016 |
| Keswick Masonic Hall Company Limited | Administrative & support | 2018 |
| Kevean Court Limited | Real estate | 2005 |
| Kevin Millican Commercial Refinishers Ltd | Wholesale & retail | 2015 |
| Keybrick Holdings Limited | Real estate | 2026 |
| Keylang Cattery Ltd | Agriculture & fishing | 2018 |
| KF Farming Limited | Agriculture & fishing | 2021 |
| Kings Performance Ltd | Wholesale & retail | 2015 |
| Kirkbride Energy Limited | Professional & scientific | 2013 |
| KIT Long Deliveries Ltd | Transport & logistics | 2026 |
| KT Window Cleaning Ltd | Administrative & support | 2021 |
| L a Foods (U.K) Limited | Hospitality | 2021 |
| L R & J a Allen | Wholesale & retail | 2018 |
| L7 Properties (Cumbria) Ltd | Real estate | 2026 |
| L8 Water Solutions Limited | Administrative & support | 2004 |
| LAB Gym & Nutrition Facility Ltd | Arts & recreation | 2021 |
| Lachstone Farms Limited | Agriculture & fishing | 2009 |
| Lake Mill Consulting Services Limited | Professional & scientific | 2018 |
| Lakeland Films Limited | Information & communication | 1987 |
| Lakes Delivery Network Ltd | Transport & logistics | 2025 |
| Lakes Diving and Snorkelling Limited | Education | 2025 |
| Lakestud Limited | Households | 1988 |
| Land-Drive Limited | Wholesale & retail | 2012 |
| Lane Head (Plumbland) Limited | Agriculture & fishing | 2008 |
| Langfauld Farm Limited | Agriculture & fishing | 2006 |
| Lantern Moss Caravan Park Limited | Real estate | 2025 |
| Leaf Industries Limited | Manufacturing | 2024 |
| Leica Lambert Limited | Construction | 2025 |
| Lewis Bell Architectural Limited | Professional & scientific | 2025 |
| Lightning Competitions UK Limited | Arts & recreation | 2023 |
| Limestone Lodges Limited | Real estate | 2005 |
| Linda ANN Enterprises Limited | Wholesale & retail | 2025 |
| Lindsay Audit and Safety Consultancy Ltd | Professional & scientific | 2025 |
| Listershire Limited | Wholesale & retail | 2023 |
| Little Jems Nursery (Cumbria) Limited | Health & social care | 2018 |
| Liz's Country Kitchen | Hospitality | 2026 |
| Lloyd Real Estate International Ltd | Real estate | 2019 |
| Lloyd`S Carpets & Furnishings Limited | Wholesale & retail | 2006 |
| LMS Stores Limited | Wholesale & retail | 2016 |
| Long Nook Limited | Real estate | 2025 |
| Longfield Agility Ltd | Arts & recreation | 2016 |
| LOW Abbey Coast Ltd | Hospitality | 2024 |
| LOW Plains Water Limited | Water & waste | 2025 |
| Lthubbard Ltd | Transport & logistics | 2025 |
| Luke Francis Fitness Ltd | Extraterritorial | 2022 |
| Lulle Bare Ltd | Wholesale & retail | 2021 |
| Lush Beauty Salon & Spa Limited | Other services | 2015 |
| LUX Hair and Tanning Salon Ltd | Other services | 2015 |
| M & S Attractions Limited | Arts & recreation | 2024 |
| M B Construction (North West) Limited | Construction | 2012 |
| M B Electrical Contractors Limited | Construction | 2001 |
| M Coulthard Logistics Ltd | Transport & logistics | 2026 |
| M Mawson Limited | Wholesale & retail | 2025 |
| M. & E. Elliott (Agricultural Merchants) Limited | Wholesale & retail | 1973 |
| M. & E. Elliott (Leisure Parks) Limited | Hospitality | 1976 |
| M.R. Hinde Building Limited | Construction | 2003 |
| Mark Singleton Decorator Limited | Construction | 2007 |
| Marsh Geomatics Ltd | Professional & scientific | 2023 |
| Marsh House Farming Company | Agriculture & fishing | 2012 |
| Mason Holdings (Cumbria) Limited | Financial services | 2026 |
| Masterpiece Fine Art Limited | Wholesale & retail | 1987 |
| Matrix Moulds and Models Limited | Manufacturing | 1996 |
| MAX OUT in the Lake District Ltd | Wholesale & retail | 2024 |
| Mcmc Holdings Limited | Real estate | 2023 |
| MDK Motors Ltd | Wholesale & retail | 2023 |
| Mens Counselling Service Ltd | Information & communication | 2024 |
| Mereside Associates Limited | Professional & scientific | 2024 |
| Messrs J Dickinson Farming Company | Agriculture & fishing | 2012 |
| Messrs J Dixon & Sons Limited | Agriculture & fishing | 2016 |
| Messrs Scoular | Agriculture & fishing | 2017 |
| Messrs Taylor Limited | Agriculture & fishing | 2006 |
| MF Haulage Ltd | Transport & logistics | 2022 |
| Michael Coates Joinery Limited | Construction | 2011 |
| Michael D Woodman Limited | Manufacturing | 2021 |
| Michael David Batts Limited | Extraterritorial | 2024 |
| Micklethwaite Farm | Agriculture & fishing | 2008 |
| Midnight Express Europe Ltd | Transport & logistics | 2025 |
| Midtown House Limited | Health & social care | 2003 |
| Mike Dowling Contracting Limited | Agriculture & fishing | 2012 |
| Mike Jones Properties Ltd | Real estate | 2025 |
| Miller Consulting Engineers Ltd | Professional & scientific | 2024 |
| Millers Contracting Limited | Agriculture & fishing | 2002 |
| Ministry of Doing Ltd | Information & communication | 2012 |
| MJ Edgar Plumbing & Heating Ltd | Construction | 2022 |
| Moors Covert Farm Ltd | Agriculture & fishing | 2025 |
| Morgan Heath Ltd | Construction | 2011 |
| Morrel Contruction Limited | Construction | 2017 |
| Morrel Management Ltd | Professional & scientific | 2023 |
| Morse Code Ltd | Professional & scientific | 2015 |