| Milthorp Apartments Management Company Limited | Real estate | 2023 |
| Mimi & Rembrandt Limited | Professional & scientific | 2024 |
| Mindmastery Labs Limited | Administrative & support | 2023 |
| Minerva Chemicals Limited | Professional & scientific | 2004 |
| Minerva Glenross Ltd | Wholesale & retail | 2017 |
| Mining Competence & Advisory Ltd | Mining & quarrying | 2018 |
| Minster View (Harrogate) Management Company Limited | Households | 2001 |
| Minxyvintage Limited | Wholesale & retail | 2020 |
| Mirts Holdings Limited | Real estate | 2020 |
| Misk for Trade Ltd | Wholesale & retail | 2021 |
| MISS1ON Limited | Wholesale & retail | 2022 |
| Missionobjective Limited | Professional & scientific | 2025 |
| Missy Baba Limited | Hospitality | 2017 |
| Mist Dental Limited | Health & social care | 2022 |
| Mister Protocol Limited | Hospitality | 2023 |
| Mistral Executive Limited | Transport & logistics | 2023 |
| Mitchell Roberts Commercial Limited | Real estate | 2002 |
| Mitchells Building and Property Services Ltd | Construction | 2024 |
| MIX My Scent Ltd | Wholesale & retail | 2018 |
| Mixed Martial Arts Ltd | Extraterritorial | 2012 |
| Mixer Ltd | Extraterritorial | 2012 |
| MJA Site Services Limited | Construction | 2019 |
| Mjam Land Ltd | Extraterritorial | 2024 |
| MJM Lofts (Harrogate) Ltd | Construction | 2023 |
| MJM Properties (Harrogate) Limited | Real estate | 2017 |
| MJN Developments Limited | Financial services | 2019 |
| MJN Marketing Limited | Information & communication | 2003 |
| MJP Elite Studios Limited | Health & social care | 2004 |
| MJP Medtech Partners Ltd | Professional & scientific | 2026 |
| MK Lanka Ltd | Hospitality | 2025 |
| MK85 Corporate Advisory Limited | Administrative & support | 2017 |
| Mkts Property Management Ltd | Real estate | 2022 |
| ML Ware Properties Ltd | Construction | 2026 |
| Mnmlsv Ltd | Extraterritorial | 2016 |
| Moben Limited | Extraterritorial | 2011 |
| Mobile Chat Limited | Information & communication | 2021 |
| Mobile Tornado Group Limited | Information & communication | 2004 |
| Mobile Truck Washing Services Limited | Transport & logistics | 2007 |
| Mobile Yorkshire Ltd | Wholesale & retail | 2022 |
| Mococo Property Limited | Real estate | 2024 |
| Modern Polyglot Translations Ltd | Professional & scientific | 2023 |
| Moduflow Engineering Solutions Limited | Manufacturing | 2024 |
| Modugroup Limited | Professional & scientific | 2024 |
| Moduliving Limited | Construction | 2025 |
| Moduloft Trustees Limited | Administrative & support | 2022 |
| Moduoffice Limited | Construction | 2018 |
| Moduroom Limited | Construction | 2017 |
| Mohamad Abdelaziz Trading Company Ltd | Wholesale & retail | 2024 |
| Mohamed ALY Qasim for Trade Ltd | Wholesale & retail | 2024 |
| Mohamed Batale Ltd | Wholesale & retail | 2024 |
| Mohammad Thoyyibi for Trade Ltd | Hospitality | 2024 |
| Moist Limited | Extraterritorial | 2026 |
| Mollie Morin Property Services Ltd | Construction | 2025 |
| Molyneuex Limited | Wholesale & retail | 2024 |
| Momil Investments (Bradford) Limited | Real estate | 1962 |
| Monarch Group Limited | Extraterritorial | 2025 |
| Monark Limited | Health & social care | 2011 |
| Money FM Ltd | Extraterritorial | 2016 |
| Money@Ifa Ltd | Financial services | 2008 |
| Monicalianaphotography Limited | Wholesale & retail | 2024 |
| Monks Close Investments Limited | Financial services | 2019 |
| Monkton Holdings Ltd | Real estate | 2019 |
| Monkton Moor Garage Ltd | Wholesale & retail | 2014 |
| Monsta Media Group (NE) Limited | Professional & scientific | 2025 |
| Montague House (Harrogate) Management Company Limited | Households | 2006 |
| Montefiore International Limited | Extraterritorial | 2026 |
| Monteverdi Securities Limited | Extraterritorial | 2026 |
| Monteys HG Ltd | Information & communication | 2023 |
| Montgomery FM Limited | Extraterritorial | 2026 |
| Montpellier Care Company Ltd | Health & social care | 2021 |
| Montpellier Design & Developments LLP | | 2017 |
| Montpellier Group Limited | Real estate | 2026 |
| Montpellier Jewellers Limited | Wholesale & retail | 2015 |
| Montpellier Mews Limited | Real estate | 2017 |
| Montpellier Property Consultants Limited | Real estate | 2013 |
| Montrose Pictures Limited | Information & communication | 2007 |
| Montyleesa Ltd | Professional & scientific | 2019 |
| MOO and BOO Limited | Wholesale & retail | 2021 |
| Mood Living Design Limited | Wholesale & retail | 2022 |
| Moodwise Yorkshire LLP | | 2022 |
| Moon International Ltd | Wholesale & retail | 2026 |
| Moonflower Songs Limited | Information & communication | 2020 |
| Moonstone (2024) Productions Limited | Arts & recreation | 1984 |
| Moor and Valley Ltd | Administrative & support | 2003 |
| Moor Catering Ltd | Hospitality | 2016 |
| Moor Pilates Limited | Other services | 2024 |
| Moore Beauty Limited | Health & social care | 2015 |
| Moorgate Court Residents Management Company Limited | Households | 2025 |
| Mooring Brothers Chimney Sweeps Ltd | Administrative & support | 2026 |
| Moorland Cavendish Group Limited | Information & communication | 2011 |
| Moorlands Garage Ltd | Wholesale & retail | 2003 |
| Moorview Kennels & Cattery Limited | Agriculture & fishing | 2012 |
| Moorview Luxury Boarding Limited | Agriculture & fishing | 2024 |
| Moosa Eyecare Limited | Health & social care | 2017 |
| Moosa Holdings Ltd | Real estate | 2015 |
| Moral Compass Consulting Ltd | Education | 2017 |
| Morgan Bradstock Limited | Other services | 2025 |
| Morgan Clare (UK) Ltd. | Wholesale & retail | 2013 |
| Morgan Westwood Limited | Extraterritorial | 2025 |
| Mornington Harrogate Limited | Households | 2007 |