| LW Consultancy Limited | Professional & scientific | 2016 |
| Lymerer Ltd | Extraterritorial | 2025 |
| Lynz Limited | Hospitality | 2018 |
| M Grant Contractors Ltd | Construction | 2024 |
| M K Cabs Ltd. | Transport & logistics | 2000 |
| M Little Superstore Ltd | Wholesale & retail | 2021 |
| M ROY Roofing Building & Renovations Ltd | Construction | 2014 |
| M&B Afro-Caribbean Market Ltd | Wholesale & retail | 2026 |
| M&M Compliance Training Services Ltd | Professional & scientific | 2022 |
| M. Thomson Groundworks Ltd. | Construction | 2011 |
| M.Barry & SON Electrical Contractors Limited | Construction | 2013 |
| M12NVD Ltd | Wholesale & retail | 2023 |
| Macintosh & Sons (Brough) Ltd | Real estate | 2018 |
| Macintosh & Sons Limited | Real estate | 2018 |
| Maclennan Construction Services Ltd | Manufacturing | 2019 |
| Macotob Solutions Ltd | Professional & scientific | 2022 |
| Making Waves Investments Ltd | Real estate | 2023 |
| Malky and Sons Bhakar Limited | Wholesale & retail | 2018 |
| Mama Goose Ltd | Hospitality | 2017 |
| Mane Attraction Studio Ltd | Other services | 2024 |
| Marand Holdings Ltd | Financial services | 2024 |
| Marc’S Garden Services Ltd | Administrative & support | 2020 |
| Mark Lockhart Joinery Ltd. | Other services | 2017 |
| Mark Patchett Ltd. | Arts & recreation | 2004 |
| Mark Smith Joinery Ltd | Construction | 2019 |
| Marko & Linton Joinery and Building Services Ltd | Manufacturing | 2020 |
| Marta Commercial Ltd | Administrative & support | 2017 |
| Martin & Sime Dance Academy Ltd | Education | 2020 |
| Martin's Building Services Limited | Construction | 2001 |
| Mascot Civils Ltd | Construction | 2014 |
| Masoka Limited | Transport & logistics | 2014 |
| Matson Mourier Architects Limited | Professional & scientific | 2024 |
| Mayfield & Easthouses Youth 2000 Project | Other services | 2000 |
| Mayfield and Easthouses Development Trust | Other services | 2007 |
| Mayshade Properties Limited | Real estate | 2014 |
| MB Developments (Scotland) Ltd | Construction | 2022 |
| MB Hall Painting & Decorating Limited | Construction | 2022 |
| MB Properties Scotland Ltd | Real estate | 2019 |
| Mcbeath Electrical Services Ltd | Construction | 2022 |
| Mccue Travel and Leisure Limited | Professional & scientific | 2000 |
| Mcgovern Lettings Ltd | Real estate | 2020 |
| Mcgovern Serviced Accommodation Ltd | Real estate | 2022 |
| Mcgowan Solutions Ltd | Professional & scientific | 2025 |
| Mckenzie Cleaning Services Scotland Ltd Ltd | Administrative & support | 2019 |
| Mclean Photo Video Limited | Professional & scientific | 2024 |
| Mcleod Installation Services Ltd. | Construction | 2004 |
| Mcpjoinery Limited | Other services | 2013 |
| Mcsubstations Ltd | Construction | 2025 |
| MD Carstore Ltd | Wholesale & retail | 2022 |
| MD Distribution Ltd | Transport & logistics | 2026 |
| MD Packaging (Scotland) Ltd | Wholesale & retail | 2003 |
| MDG Global Holdings Ltd | Financial services | 2022 |
| Meadow Tech Limited | Information & communication | 2015 |
| Meadowbank Gymnastics Club | Arts & recreation | 2015 |
| Meadowbank Karate Group Limited | Education | 2022 |
| Meadowfield Garage Ltd | Wholesale & retail | 2014 |
| Meere Marketing Limited | Professional & scientific | 2023 |
| Meerkat Designs Limited | Wholesale & retail | 2025 |
| Mega Commer Ltd | Wholesale & retail | 2021 |
| Mega Commerce Ltd | Wholesale & retail | 2021 |
| Melbarry Accountants Limited | Professional & scientific | 2014 |
| Menco Resolve Ltd | Administrative & support | 2022 |
| Meraki Concept Studio Ltd | Administrative & support | 2017 |
| Meritorium Springvalley Limited | Real estate | 2010 |
| Metrology Total Solutions Limited | Information & communication | 2015 |
| MG Woodwork Edinburgh Ltd | Construction | 2021 |
| MGF Management Services Limited | Construction | 2015 |
| MIB Consultancy Services Ltd | Professional & scientific | 2021 |
| Midge Fitness Ltd | Arts & recreation | 2023 |
| Midlothian Decorating Centre Ltd | Wholesale & retail | 2025 |
| Midlothian Fish Bar Ltd | Hospitality | 2026 |
| Midlothian Football Centre C.I.C. | Arts & recreation | 2018 |
| Midlothian Music School CIC | Education | 2025 |
| Midlothian Physiotherapy LLP | | 2008 |
| Midlothian Properties Ltd | Real estate | 2025 |
| Midlothian Property Company Limited | Real estate | 2019 |
| Midlothian Roofing Services Limited | Construction | 2005 |
| Midlothian Sure Start | Health & social care | 2001 |
| Midlothian Taxis DOT COM Limited | Transport & logistics | 2021 |
| Midlothian Tiling Services Ltd | Construction | 2020 |
| Midlothian Young People's Advice Service | Health & social care | 1999 |
| Midlothian-Cabs Ltd | Transport & logistics | 2023 |
| Mike the Builder Ltd | Construction | 2026 |
| Miko Property Ltd | Real estate | 2025 |
| Miller Brown Properties Ltd | Real estate | 2021 |
| Mint FIG Ltd | Wholesale & retail | 2014 |
| Minty Frenchy Supplies Limited | Wholesale & retail | 2025 |
| Miradi Ltd | Information & communication | 2025 |
| MJC Business Consulting Ltd | Professional & scientific | 2024 |
| MJS Height Specialist Ltd | Construction | 2024 |
| MKN Motors Ltd | Wholesale & retail | 2015 |
| Mkpx Ltd | Information & communication | 2025 |
| ML Specialist Finance Ltd | Financial services | 2023 |
| MM Superstores Ltd | Wholesale & retail | 2025 |
| MMW Joinery Limited | Construction | 2019 |
| MN Akbar Properties Limited | Households | 2022 |
| MN Healing Arts Limited | Health & social care | 2026 |
| Modern Film Composer LLP | | 2017 |
| Moffat Group Ltd | Construction | 2023 |
| Momentous Production Ltd | Information & communication | 2022 |