| MAX Plan 6 Limited | Other services | 2016 |
| MAX Plan London Ltd | Construction | 2020 |
| Maximal Power Limited | Professional & scientific | 2004 |
| Mayfield Place LLP | | 2015 |
| Mayo Consulting and Training Limited | Professional & scientific | 2014 |
| MB Consulting (Kent) Limited | Professional & scientific | 2019 |
| MB66 Ltd | Professional & scientific | 2022 |
| Mbecanterbury Ltd | Administrative & support | 2023 |
| Mbeproperty Ltd. | Real estate | 2014 |
| MBH Productions Ltd | Other services | 2018 |
| MBM Balance Ltd | Professional & scientific | 2020 |
| Mbm&Co. Ltd. | Information & communication | 2015 |
| Mboh Properties Limited | Real estate | 2026 |
| MBR Consultancy Services Ltd | Information & communication | 2025 |
| MBR Group Limited | Manufacturing | 2019 |
| Mbservices Consultancy Ltd | Professional & scientific | 2022 |
| Mcallister Assurance Consultants Limited | Financial services | 1977 |
| Mcallister Pharma Consulting Ltd | Professional & scientific | 2024 |
| MCB Agencies LLP | | 2019 |
| Mccrory Training Limited | Professional & scientific | 2019 |
| Mccurrach Web Solutions Ltd | Information & communication | 2026 |
| Mcguire Property Management Limited | Real estate | 2020 |
| Mchills Limited | Information & communication | 2008 |
| MCI Australia Limited | Administrative & support | 2008 |
| Mclaire Estates Ltd | Hospitality | 2025 |
| Mclaughlin Kent Limited | Construction | 2019 |
| Mcmillan Alvarez Associates Ltd | Professional & scientific | 2015 |
| Mcrofe Ltd | Health & social care | 2015 |
| MCS Technical Services Ltd | Manufacturing | 2019 |
| MD Electrical (S.E.) Limited | Construction | 2017 |
| MD Electrical Fire and Security Ltd | Construction | 2020 |
| MD Electrical Mechanical Limited | Construction | 2023 |
| MDD Capital Limited | Construction | 2024 |
| MDD Group Architecture & Interiors Ltd | Construction | 2025 |
| ME Kent Limited | Hospitality | 2025 |
| Meadowedge Investment Limited | Real estate | 2021 |
| Meadows Essential Oils Limited | Wholesale & retail | 2015 |
| Meadowview Cottage Limited | Real estate | 2024 |
| Measurement Systems Consultancy Limited | Professional & scientific | 2005 |
| Meathplanthire Ltd | Wholesale & retail | 2024 |
| Mechconsult Ltd | Construction | 2024 |
| Medco (Cccu) Limited | Education | 2003 |
| Medi 1999 Ltd | Transport & logistics | 2024 |
| Media Angels (UK) Limited | Administrative & support | 2003 |
| Medicine Design Limited | Professional & scientific | 2021 |
| Medmerry Park Limited | Hospitality | 1983 |
| Medusa Event Management Ltd | Hospitality | 2025 |
| Medway Preservation & Development Limited | Arts & recreation | 2016 |
| Medway Preservation Limited | Arts & recreation | 2015 |
| Medway Therapy Limited | Health & social care | 2024 |
| Medway Town Football Club CIC | Arts & recreation | 2026 |
| Meet Cosy Ltd | Wholesale & retail | 2025 |
| Mega Associates Limited | Wholesale & retail | 2025 |
| Megalithic Prints Ltd | Arts & recreation | 2022 |
| Melior Design Ltd | Professional & scientific | 2018 |
| Melo Transports Limited | Transport & logistics | 2018 |
| Melody Fire Ltd | Construction | 2019 |
| Melrose Contractors Ltd | Real estate | 2022 |
| Memina Capital Limited | Real estate | 2008 |
| Mendtogether CIC | Other services | 2026 |
| Mental Toughness Institute Ltd | Education | 2020 |
| Mentorme Ltd | Education | 2022 |
| Mera Creative Studios Ltd | Information & communication | 2023 |
| Mercery Court Limited | Households | 2009 |
| Merchants Mews Management Limited | Households | 2007 |
| Merefield's Holdings Limited | Financial services | 2022 |
| Meridian Advisers Ltd | Professional & scientific | 2022 |
| Meridian Community Care Limited | Health & social care | 2002 |
| Merlin Social Care Limited | Health & social care | 2013 |
| Merrymove Limited | Administrative & support | 2009 |
| Mersham Productions Limited | Arts & recreation | 1956 |
| Metal Legacy Limited | Wholesale & retail | 2023 |
| Metal Master Canterbury Ltd | Manufacturing | 2017 |
| Metastable Engineering Ltd | Professional & scientific | 2016 |
| Meteorik Limited | Information & communication | 2023 |
| Metis Digital Services Limited | Information & communication | 2023 |
| Metis Technology Solutions Ltd | Information & communication | 2013 |
| Mexetto Restaurants Ltd | Hospitality | 2026 |
| Meze Zara Ltd | Hospitality | 2019 |
| MFG Bekesbourne Ltd | Hospitality | 2019 |
| MFJ (NO. 3) Limited | Real estate | 2010 |
| MG World Trading Ltd | Professional & scientific | 2013 |
| MGC Recovery Ltd | Wholesale & retail | 2026 |
| Mhchem Ltd | Wholesale & retail | 2025 |
| MI Code Ltd | Information & communication | 2023 |
| Michaels Trading Limited | Manufacturing | 2023 |
| Mickle Print (Canterbury) Limited | Manufacturing | 2004 |
| Micode Medical Ltd | Information & communication | 2025 |
| Micro Roastery Limited | Hospitality | 2018 |
| MID Kent Aviation Ltd | Real estate | 2024 |
| Middleton Taylor Ltd | Professional & scientific | 2018 |
| Midlumes Consultancy Services Limited | Wholesale & retail | 2025 |
| Midnight Seller Limited | Wholesale & retail | 2025 |
| MIG Golf Ltd | Wholesale & retail | 2024 |
| MIG Tanning Ltd | Other services | 2025 |
| Mikes Properties Limited | Households | 2017 |
| Mile Property Group Holdings Limited | Real estate | 2025 |
| Mile Property Group Ltd | Construction | 2017 |
| Miles Healthcare Ltd | Health & social care | 2021 |
| Miles Way Management Company Limited | Real estate | 1987 |