| Lighting Media Limited | Administrative & support | 2025 |
| Lilly Collections Ltd | Wholesale & retail | 2025 |
| Limitless Graphics Limited | Professional & scientific | 2018 |
| Lineal Properties Ltd | Real estate | 2025 |
| Lionsdale Investments Ltd | Real estate | 2025 |
| Lissdo Limited | Administrative & support | 2020 |
| LM & Sons Recruitment Ltd | Administrative & support | 2026 |
| Loadsure Bags Limited | Wholesale & retail | 2025 |
| Lodge Drive Lettings Limited | Real estate | 2026 |
| Longley Property Investment Ltd | Real estate | 2023 |
| Lostmixesuk Ltd | Arts & recreation | 2021 |
| Love-Buttons Ltd | Wholesale & retail | 2014 |
| Lower Hopton Chapel Court Residents Limited | Real estate | 2013 |
| LPD Associates Ltd | Administrative & support | 2015 |
| Lucy Grace Limited | Wholesale & retail | 2024 |
| Lullaby Lounge Pet Spa and Grooming Studio Ltd | Other services | 2025 |
| M & S Installations UK Ltd | Construction | 2021 |
| M R Wood & Co. Ltd | Professional & scientific | 2003 |
| M S Hunt Limited | Information & communication | 2012 |
| M&L Cards Ltd | Wholesale & retail | 2023 |
| M-Press Electrical Ltd | Manufacturing | 2025 |
| M. Stainthorp (Solid Fuel) Limited | Wholesale & retail | 2005 |
| M. Stead & Sons Co. Ltd | Construction | 2002 |
| M.S.L. Services Limited | Construction | 1994 |
| MAC Qc/Qa Ltd | Manufacturing | 2023 |
| Machinery Services UK Limited | Manufacturing | 2006 |
| Made by Macorison Ltd | Construction | 2023 |
| MAL & J Lettings Ltd | Real estate | 2026 |
| Maple Groundcare Limited | Administrative & support | 2024 |
| Marant Consulting Limited | Professional & scientific | 2024 |
| Mark Chapman Decorators Ltd | Other services | 2007 |
| Market Fusion Limited | Professional & scientific | 2020 |
| Marlin Images Commercial Limited | Professional & scientific | 2007 |
| Marquees for ALL Occasions Ltd | Administrative & support | 2019 |
| Matio Traders Ltd | Hospitality | 2022 |
| Matt Hartley Ltd | Other services | 2025 |
| Matthew Adgie Homes Ltd | Real estate | 2026 |
| Maughans Bakery Limited | Manufacturing | 2024 |
| Maughans Caterers Limited | Manufacturing | 1945 |
| Maven People Limited | Administrative & support | 2015 |
| Maximillano (Mirfield) Ltd | Hospitality | 2025 |
| MAY Chauffeur Service Limited | Transport & logistics | 2021 |
| Mayhem Made Ltd | Manufacturing | 2022 |
| MC Developments W.Y Ltd | Construction | 2025 |
| Mdmr Limited | Manufacturing | 2000 |
| Medspro Ltd | Health & social care | 2013 |
| MEE Property & Development Limited | Construction | 2014 |
| MEL Developments (Yorkshire) Ltd | Manufacturing | 2018 |
| Mentor Intro Ltd | Administrative & support | 2025 |
| Meraki Haus of Beauté Ltd | Other services | 2020 |
| Mfield Trading Ltd | Wholesale & retail | 2021 |
| MG Lifestyle Ltd | Other services | 2022 |
| MI & S Management Limited | Real estate | 2019 |
| Miage Limited | Wholesale & retail | 2010 |
| Microblading by Kate Ltd | Other services | 2024 |
| Micrographics Ltd | Information & communication | 1983 |
| MID Craigie Bess Limited | Energy | 2023 |
| MIG Property Management Limited | Real estate | 2021 |
| MIK UK & International Haulage Ltd | Transport & logistics | 2025 |
| Milek & Co Ltd | Manufacturing | 2017 |
| Milestone UKI Limited | Wholesale & retail | 2025 |
| Mindful Maker CIC | Education | 2023 |
| Minnanjey Mirfield Daycare Limited | Education | 2019 |
| Mirfield Auto Spares Limited | Wholesale & retail | 2009 |
| Mirfield Automotive Spares Limited | Wholesale & retail | 2017 |
| Mirfield Barbers Huddersfield Ltd | Other services | 2024 |
| Mirfield Barbers Ltd | Other services | 2022 |
| Mirfield Brewery Limited | Manufacturing | 2020 |
| Mirfield Building Plastics Limited | Wholesale & retail | 2015 |
| Mirfield Designs Limited | Professional & scientific | 2016 |
| Mirfield Electrical Installations Ltd | Construction | 2014 |
| Mirfield Little Theatre Ltd | Hospitality | 2025 |
| Mirfield M.O.T Centre Limited | Wholesale & retail | 2014 |
| Mirfield Madressa Tutor Group Ltd | Education | 2025 |
| Mirfield Medical Practice Limited | Health & social care | 2019 |
| Mirfield Mill Carpets Limited | Other services | 2014 |
| Mirfield Miniatures Ltd | Wholesale & retail | 2021 |
| Mirfield Monastery Ltd | Hospitality | 2013 |
| Mirfield Mowers Limited | Wholesale & retail | 2016 |
| Mirfield Podiatry and Chiropody Ltd | Health & social care | 2024 |
| Mirfield Town Barbers Ltd | Other services | 2026 |
| Missing Head Ltd | Information & communication | 2011 |
| Mitha Enterprise Ltd | Real estate | 2017 |
| Mitha Partnerships Limited | Financial services | 2017 |
| MJ 123 Ltd | Real estate | 2021 |
| MJB Groundcare Solutions Limited | Construction | 2016 |
| MK1 Consultants Limited | Professional & scientific | 2013 |
| MMA Super Ltd | Education | 2023 |
| MMB Optics Ltd | Health & social care | 2023 |
| Modu Exhibitions Ltd | Real estate | 2015 |
| Monarch Standard Ltd | Wholesale & retail | 2025 |
| Monkey Business Events Ltd | Other services | 2009 |
| Monolith Restoration Ltd | Construction | 2025 |
| Moorhouse Engineering Ltd | Professional & scientific | 2023 |
| More Than Flowers Ltd | Wholesale & retail | 2018 |
| Morten Burton Ltd | Professional & scientific | 2022 |
| Morthanveld Publishing Ltd | Information & communication | 2013 |
| Motoraid App Ltd | Transport & logistics | 2026 |
| Mowbray NDT Services Ltd | Professional & scientific | 2014 |
| Moxon Property Ltd | Real estate | 2021 |