| Lion Construction Group Ltd | Real estate | 2019 |
| Lisa Kate Health and Fitness Limited | Arts & recreation | 2020 |
| Lisa Lizzio Consulting Ltd | Professional & scientific | 2015 |
| Little Brooke Limited | Health & social care | 2023 |
| Little Corner Bakery Ltd | Wholesale & retail | 2025 |
| Little Rays of Sunshine Ltd | Health & social care | 2025 |
| Little Trees Childcare Ltd | Health & social care | 2024 |
| Livefield Festivals and Events Limited | Administrative & support | 2021 |
| Liversedge Football Club Limited | Arts & recreation | 1999 |
| LJS Outlet Ltd | Wholesale & retail | 2022 |
| LK Healthcare Consulting Ltd | Information & communication | 2024 |
| Lloyd Simpson Incentives Limited | Professional & scientific | 1994 |
| LM Contracts (Yorkshire) Limited | Construction | 2009 |
| LMB (West Yorkshire) Holdings Ltd | Financial services | 2022 |
| LMB Electrical Services Limited | Energy | 2012 |
| LMB Group (Yorkshire) Limited | Professional & scientific | 2012 |
| LMB Mechanical Services Limited | Construction | 2006 |
| LMN Education Ltd | Other services | 2023 |
| Loft Creative Limited | Other services | 2025 |
| Loh-Kee Ltd | Real estate | 2021 |
| Longhost Limited | Real estate | 1985 |
| Longley Paving Limited | Construction | 2023 |
| Lost Car Key Yorkshire Limited | Other services | 2014 |
| Loughran Properties Ltd | Real estate | 2025 |
| Lovedreambeds Ltd | Wholesale & retail | 2021 |
| LP Freight Limited | Transport & logistics | 2014 |
| LP Hair (Yorkshire) Limited | Other services | 2018 |
| LRS Flooring Ltd | Construction | 2025 |
| LS Flooring 85 Limited | Construction | 2022 |
| LS Lettings Ltd | Real estate | 2011 |
| LS20 Boxing ABC Ltd | Arts & recreation | 2025 |
| LS6ITALIAN Ltd | Hospitality | 2025 |
| LSB Services Yorkshire Limited | Other services | 2021 |
| LT Landscapes Yorkshire Ltd | Administrative & support | 2015 |
| Lucid IT Solutions Ltd | Information & communication | 2012 |
| Lucid Partnership LLP | | 2013 |
| Lucre Holdings Limited | Professional & scientific | 2008 |
| Lucre London Limited | Professional & scientific | 2007 |
| Lucre Marketing Limited | Professional & scientific | 2004 |
| Luka Security Services Ltd | Administrative & support | 2024 |
| Lusu Sports Limited | Education | 2016 |
| Luxe Caravans Ltd | Real estate | 2025 |
| Luxua Properties Ltd | Real estate | 2024 |
| Luxury Lofts Limited | Construction | 2016 |
| LV PMO Ltd | Professional & scientific | 2018 |
| Lychhee Ltd | Information & communication | 2025 |
| Lydia Consultancy Limited | Professional & scientific | 2020 |
| Lyft Developments Limited | Construction | 2025 |
| M & J Smith Properties Limited | Real estate | 2025 |
| M B P International Ltd | Water & waste | 2022 |
| M C Stores (Cleckheaton) Ltd | Wholesale & retail | 2023 |
| M Drummond Construction Limited | Construction | 2019 |
| M Flanagan Consultancy Ltd | Information & communication | 2022 |
| M Hirst Holdings Limited | Financial services | 2019 |
| M I D Motor Company Limited | Wholesale & retail | 2007 |
| M J Finance Limited | Real estate | 2025 |
| M J Motors (Yorkshire) Limited | Wholesale & retail | 2019 |
| M&E Solutions Limited | Construction | 2025 |
| M&H Hospitality Ltd | Hospitality | 2025 |
| M. L. Stainless Fabrications Limited | Manufacturing | 2005 |
| M.C.P. (Pipelines) Limited | Wholesale & retail | 1998 |
| M.N.Couriers Limited | Transport & logistics | 2002 |
| M.T. Properties (Yorkshire) Limited | Real estate | 2013 |
| MAB Property Services Ltd | Construction | 2024 |
| Machine Engineering Services Limited | Manufacturing | 2001 |
| Maclean Scaffolding Limited | Extraterritorial | 2014 |
| Macmae Holdings Limited | Professional & scientific | 2007 |
| Macorison Accountants Limited | Professional & scientific | 2003 |
| MAD Hatter Entertainment UK Limited | Information & communication | 2020 |
| Madison Gardens Management Limited | Households | 2020 |
| Magik Lamp Limited | Professional & scientific | 2022 |
| Magna Pubs Limited | Professional & scientific | 2007 |
| Magpie Lettings Limited | Real estate | 2020 |
| Maintenance Solutions 4 Business Ltd | Administrative & support | 2016 |
| Malt & Munch Limited | Hospitality | 2019 |
| Mama Roma Casa Limited | Hospitality | 2016 |
| Manage My Round Ltd | Information & communication | 2025 |
| Mandsinteriors Ltd | Wholesale & retail | 2012 |
| Manningstead Limited | Real estate | 1978 |
| Manor House Holdings Ltd | Financial services | 2018 |
| Marcus (Bradford) Limited | Transport & logistics | 1964 |
| Marie Lees Public Relations Ltd | Professional & scientific | 2020 |
| Mark Fretwell Limited | Construction | 2019 |
| Mark Hobson Plasterers Limited | Construction | 2010 |
| Marketing Mechanic Limited | Administrative & support | 2014 |
| Marketlink Limited | Professional & scientific | 2015 |
| Marley Bespoke Joinery Ltd | Construction | 2021 |
| Marshall Fairley Investments Limited | Extraterritorial | 1993 |
| Marshall's KOI Limited | Wholesale & retail | 2024 |
| Matt Risebrow Limited | Arts & recreation | 2017 |
| Matthew Bouch Limited | Administrative & support | 2019 |
| Mattress Matters Ltd | Wholesale & retail | 2021 |
| Mauritius Leisure Activities Ltd | Arts & recreation | 2019 |
| Maverick Motorcycle World Ltd | Other services | 2022 |
| Maverick Motorcycles Ltd | Extraterritorial | 2023 |
| Maverick Performance Products Ltd | Arts & recreation | 2022 |
| Maverick Technology Group Ltd | Other services | 2020 |
| Maverick Yamaha World Ltd | Other services | 2022 |
| MB Electrical (Yorkshire) Ltd | Construction | 2017 |
| MB Installs Limited | Construction | 2025 |