| K.L.S. [Cumbria] Limited | Health & social care | 2002 |
| K9 Fertility Clinic Cumbria Limited | Agriculture & fishing | 2021 |
| KCC Property Solutions Ltd | Real estate | 2024 |
| Kdtech Electrical Ltd | Construction | 2023 |
| Keeklemere Limited | Agriculture & fishing | 2008 |
| KEL Properties Estate Ltd | Real estate | 2023 |
| KEL Utilities Limited | Construction | 2010 |
| Kells Development Group Limited | Construction | 2009 |
| Ken's Teeth Limited | Health & social care | 2020 |
| Kerry Park Dental Practice Limited | Health & social care | 2019 |
| Kevin Dickinson Ltd | Construction | 2024 |
| Kevin Dickinson Upvc Limited | Construction | 2004 |
| Kevin Thompson Limited | Agriculture & fishing | 2016 |
| Key 2 Sports & Nutrition Limited | Wholesale & retail | 2011 |
| Key 2 Sports Limited | Wholesale & retail | 2022 |
| KF Optical Ltd | Wholesale & retail | 2025 |
| Kievie Limited | Administrative & support | 2019 |
| Kirkby Services Limited | Professional & scientific | 1998 |
| Kirkland Carpets and BED Centre Limited | Wholesale & retail | 2025 |
| Kirsten Prosser Financial Insights Limited | Professional & scientific | 2017 |
| KJW Transport Limited | Transport & logistics | 2025 |
| KM Property Services (Cumbria) Limited | Real estate | 2024 |
| KMC Health & Wellness Ltd | Other services | 2024 |
| KMH Roofing Ltd | Construction | 2024 |
| Knock Murton Limited | Construction | 2015 |
| Kp-Recovery Zone Ltd | Other services | 2025 |
| Kristo Investments Limited | Real estate | 2018 |
| KT Engineering Consultants Ltd | Professional & scientific | 2023 |
| KTK Electrical Ltd | Construction | 2024 |
| KTL Commissioning Services Ltd | Other services | 2026 |
| Kumquat Stays Ltd | Hospitality | 2024 |
| KWT Joinery Ltd | Construction | 2025 |
| Kyle Bickley Racing Ltd | Arts & recreation | 2017 |
| L & K Curwen Limited | Construction | 2009 |
| L & L Property Contractors Limited | Construction | 2018 |
| L J Tyson Ltd | Health & social care | 2023 |
| L&D (Cumbria) Limited | Hospitality | 2026 |
| L-J Marine Ltd | Professional & scientific | 2008 |
| Lake District Joinery Services Limited | Construction | 2023 |
| Lake District Property Services Ltd | Construction | 2026 |
| Lake District Rentals Ltd | Real estate | 2023 |
| Lake Hunts Limited(The) | Hospitality | 1977 |
| Lake View Bassenthwaite Ltd | Real estate | 2025 |
| Lakeland Audio Visual Ltd | Administrative & support | 2026 |
| Lakeland Cosmetics Limited | Manufacturing | 2008 |
| Lakeland GAS Limited | Construction | 2012 |
| Lakeland Homes Ltd. | Construction | 1999 |
| Lakeland Lettings Ltd | Real estate | 2022 |
| Lakeland Plastering Ltd | Construction | 2002 |
| Lakeland Rowing Club | Arts & recreation | 2017 |
| Lakeland Stone Ltd | Manufacturing | 2018 |
| Lakes Bespoke Plastering Ltd | Construction | 2023 |
| Lakes College Enterprises Ltd | Hospitality | 2020 |
| Lakes Escapes Ltd | Arts & recreation | 2017 |
| Lakes Group Ltd | Hospitality | 2025 |
| Lakes Hospitality Services Limited | Wholesale & retail | 2019 |
| Lakes Letting Agent Limited | Real estate | 2019 |
| LAL Education Management Services Ltd | Administrative & support | 2022 |
| Lamont Pridmore (West Cumbria) Limited | Professional & scientific | 2003 |
| Lamont Pridmore Asset & Wealth Management Limited | Financial services | 2013 |
| Lamont Pridmore Audit Ltd | Extraterritorial | 2015 |
| Lancashire Competitions Ltd | Other services | 2023 |
| Lansdowne Books Limited | Information & communication | 2023 |
| Lavish Lengths Ltd | Other services | 2025 |
| Lawson's Training Centre Limited | Education | 1990 |
| Lawsons Crane Hire Limited | Administrative & support | 2004 |
| LC Electrical Services Limited | Construction | 2023 |
| Lcrwl Limited | Real estate | 2024 |
| LD Lettings Ltd | Real estate | 2021 |
| Learning Land Limited | Education | 2004 |
| Leisure Spot Ltd | Hospitality | 2023 |
| LEL Construction Ltd | Construction | 2025 |
| LEL Mechanical & Electrical Engineering Ltd | Manufacturing | 2025 |
| LEL Nuclear Ltd | Construction | 2022 |
| LES. Bennett Furnishings Limited | Real estate | 1976 |
| LG Fabrications (UK) Limited | Professional & scientific | 2026 |
| LGL Services Ltd | Manufacturing | 2026 |
| LHA Recovery Zone CIC | Health & social care | 2026 |
| Life Wealth Plan Limited | Extraterritorial | 2017 |
| Lifting Expertise Ltd | Manufacturing | 2025 |
| Lime Hair Studio (Cumbria) Limited | Other services | 2016 |
| Lime House (Cumbria) Ltd | Real estate | 2025 |
| Limitless X Competitions Ltd | Professional & scientific | 2023 |
| Lindavid Consultancy Ltd | Professional & scientific | 2023 |
| Linden Upholstery Limited | Manufacturing | 1991 |
| Lion-I Ltd | Other services | 2017 |
| Lisa's Lodges Ltd | Construction | 2023 |
| Little House of Play Limited | Arts & recreation | 2022 |
| Little Stars (Workington) Limited | Education | 2007 |
| Living for Life (Cumbria) Limited | Health & social care | 2010 |
| LJH Property (Cumbria) Limited | Hospitality | 2023 |
| LN Catering Cumbria Ltd | Hospitality | 2025 |
| Lochaven Ltd | Arts & recreation | 2025 |
| Lorton Vale Sawmill Ltd | Manufacturing | 2024 |
| Lowca Lane Business Park Ltd | Construction | 2017 |
| Loweswater Holiday Cottages Limited | Hospitality | 2002 |
| Lowmill Energy Ltd | Administrative & support | 2024 |
| Lowther Lounge Cafe Limited | Hospitality | 2025 |
| Lsautos Ltd | Extraterritorial | 2024 |
| LSW Property Group Ltd | Real estate | 2022 |