| Lancaster Street Storage Limited | Transport & logistics | 2018 |
| Lancs & Cumbria Lifts (UK) Ltd | Wholesale & retail | 2009 |
| Landscape Solutions Limited | Administrative & support | 1999 |
| Langwathby Properties Limited | Real estate | 2017 |
| Larch Cottage Nurseries Limited | Agriculture & fishing | 2000 |
| Lariston LLP | | 2002 |
| LAT Developments Limited | Real estate | 2019 |
| Lautre Limited | Wholesale & retail | 2025 |
| Lazonby and District Swimming Pool Association Limited | Arts & recreation | 2008 |
| Lazonby Pool Campsite Limited | Arts & recreation | 2023 |
| LBA Property Limited | Real estate | 2018 |
| LDG Motors Ltd | Wholesale & retail | 2025 |
| LE Drus Ltd | Health & social care | 2010 |
| Leaderboard Performance Limited | Professional & scientific | 2017 |
| Leap Financial Planning Ltd | Financial services | 2025 |
| LED by Leaders Ltd | Professional & scientific | 2025 |
| LEE Holliday Brickwork Ltd | Construction | 2015 |
| Legacy Software Limited | Information & communication | 2012 |
| Leighannsplace Ltd | Hospitality | 2026 |
| LEO Houlding Limited | Arts & recreation | 2002 |
| LES Watson Transport Limited | Transport & logistics | 2002 |
| Lewis Historic Building Consultants Ltd | Administrative & support | 2018 |
| Leyline North Limited | Arts & recreation | 2022 |
| Lianndre Limited | Health & social care | 2022 |
| Liddle Contracts Ltd | Construction | 2025 |
| Life Dental Services Limited | Real estate | 2017 |
| Life Raft Media Limited | Information & communication | 2011 |
| Lifestyle Property Ltd | Real estate | 2025 |
| Lifetime Home Care Limited | Health & social care | 2011 |
| Light Library Ltd | Wholesale & retail | 2018 |
| Lightfoot Medical Limited | Health & social care | 2025 |
| Lightning Ridge Limited | Professional & scientific | 2008 |
| Lightupu Ltd | Wholesale & retail | 2024 |
| Limitless Fitness and Boxing Limited | Arts & recreation | 2026 |
| Link Engineering and Project Services Limited | Professional & scientific | 2024 |
| Lion Hire Ltd | Administrative & support | 2018 |
| Lions Inc. Limited | Financial services | 2020 |
| Lisco Construction & Developments Ltd | Construction | 2025 |
| Little Bears Childminding Ltd | Health & social care | 2025 |
| Liverpool Drones Limited | Information & communication | 2017 |
| LJB Consultancy Ltd | Professional & scientific | 2022 |
| Llama Karma Kafe Limited | Hospitality | 2019 |
| Lloyd Brothers (Scotland) Limited | Real estate | 1973 |
| Lloyd IP Limited | Administrative & support | 1999 |
| Lloyd Square Consultancy Limited | Professional & scientific | 2012 |
| LM ST Helens Limited | Health & social care | 2019 |
| Localdirect Ltd | Information & communication | 2011 |
| Lockhart Leisure Ltd | Administrative & support | 2011 |
| Locust Sports UK Limited | Wholesale & retail | 2015 |
| Lonsdale Box CUP Ltd | Arts & recreation | 2019 |
| Lonsdale Park (Hackthorpe) Limited | Construction | 2019 |
| Lonsdale Settled Estates Limited | Real estate | 2006 |
| Lookin HOW Limited | Real estate | 2002 |
| Lookout Films Limited | Information & communication | 2011 |
| Lords Plain Farm | Professional & scientific | 2007 |
| Lorimers Property Management Ltd | Real estate | 2020 |
| Love Solar Ltd | Construction | 2010 |
| LOW Carbon Fuels Limited | Professional & scientific | 2011 |
| LOW Pittington Investments Limited | Financial services | 2013 |
| Loweswater Consulting Limited | Professional & scientific | 2010 |
| Lowther Castle and Gardens Trust | Arts & recreation | 2007 |
| Lowther Castle Limited | Administrative & support | 2003 |
| Lowther Estates Ltd | Households | 2021 |
| Lowther Forestry Group Limited | Agriculture & fishing | 1997 |
| Lowther Group Ltd | Financial services | 2018 |
| Lowther Holiday Park 2 Limited | Hospitality | 2023 |
| Lowther Holiday Park Limited | Hospitality | 1971 |
| Lowther Limited | Professional & scientific | 2025 |
| Lowther Park Farms Limited | Agriculture & fishing | 1960 |
| Lowther Trustees (1) Limited | Administrative & support | 2006 |
| Lowther Trustees (2) Limited | Administrative & support | 2006 |
| Lowther Trustees (3) Limited | Administrative & support | 2006 |
| Lowther Trustees (4) Limited | Administrative & support | 2006 |
| Lowthian Limited | Wholesale & retail | 2025 |
| LPC Property Developments Ltd | Real estate | 2022 |
| LTV Solutions Ltd | Professional & scientific | 2022 |
| Lucas Leisure Limited | Hospitality | 2011 |
| Lucy Loves Ltd | Wholesale & retail | 2021 |
| Lugar Developments Limited | Construction | 2020 |
| Luke Bainbridge Services Ltd | Professional & scientific | 2024 |
| Lune Holdings Limited | Financial services | 2015 |
| Lunesdale House Management Company Limited | Real estate | 1993 |
| Lunesdale Rise (Kirkby Lonsdale) Limited | Construction | 2022 |
| Lunesdale United Football Club Limited | Arts & recreation | 2005 |
| Luxe Heat Limited | Construction | 2025 |
| Lyle Farming Company | Agriculture & fishing | 2020 |
| Lyon Equipment Limited | Manufacturing | 1995 |
| Lyon Equipment Trustees Limited | Professional & scientific | 2022 |
| Lyon Logistics Limited | Extraterritorial | 2002 |
| Lyon Work & Rescue Ltd. | Extraterritorial | 1999 |
| Lyson Limited | Manufacturing | 2023 |
| Lyvennet Community Trust | Real estate | 2009 |
| Lyvennet Fencing & Contract Services Limited | Manufacturing | 2008 |
| M & E Partnership (Manchester) Limited | Professional & scientific | 2025 |
| M & E Partnership Limited | Professional & scientific | 1997 |
| M & T Builders Limited | Construction | 2022 |
| M Atkinson Building Contractors Limited | Construction | 2022 |
| M C Beaty Limited | Construction | 2014 |
| M C Ferguson (Penrith) Ltd | Other services | 2020 |
| M D Bailey Ltd | Real estate | 2024 |