| Minuteman Press Oxford Ltd | Manufacturing | 2011 |
| Mipela Ltd | Real estate | 2025 |
| Mirada Medical Group Limited | Financial services | 2022 |
| Mirada Medical Limited | Wholesale & retail | 2008 |
| Mirage Interior Specialists Ltd | Professional & scientific | 2026 |
| Mirkoys Ltd | Wholesale & retail | 2025 |
| Mirl Investments Ltd | Administrative & support | 2011 |
| Mirrord Limited | Wholesale & retail | 2022 |
| MIS International Ltd | Administrative & support | 2022 |
| Misbourne Design Associates Limited | Professional & scientific | 2018 |
| Mise EN Place Deliveries Limited | Hospitality | 2014 |
| Missionlink UK Ltd | Other services | 2023 |
| Mistco Limited | Information & communication | 1989 |
| Misty Day Limited | Professional & scientific | 2017 |
| Mitorx Therapeutics Limited | Professional & scientific | 2021 |
| Mitre Yard Properties (2020) Limited | Real estate | 2019 |
| Mitre Yard Properties (Lettings) Limited | Real estate | 2024 |
| Mitsha Investment Limited | Real estate | 2023 |
| Mizu 280 Limited | Hospitality | 2025 |
| Mizu Summertown Limited | Real estate | 2025 |
| MJB Investment Limited | Real estate | 2022 |
| MJF & CLF Limited | Financial services | 2013 |
| MJS Games Ltd | Wholesale & retail | 2023 |
| MJS Plumbing & Electrical Ltd | Construction | 2021 |
| MJS Property Holdings Oxford Ltd | Real estate | 2022 |
| MK Dogar Limited | Real estate | 2015 |
| MK ILA Limited | Professional & scientific | 2025 |
| MK9 Services Ltd | Wholesale & retail | 2025 |
| Mkas Group Ltd | Professional & scientific | 2026 |
| MKB Bespoke Travel Ltd | Administrative & support | 2019 |
| MKK Foods Limited | Hospitality | 2019 |
| Mksk Consulting Ltd | Professional & scientific | 2017 |
| Ml&H Ltd | Health & social care | 1996 |
| MLD Distribution Ltd | Wholesale & retail | 2013 |
| Mld-Uk | Other services | 1995 |
| Mlos Investments Ltd | Administrative & support | 2020 |
| MLS Defi Ltd | Information & communication | 2022 |
| MM Electrical Services (Oxford) Limited | Construction | 2012 |
| MMC Training & Consultancy Ltd | Construction | 2020 |
| Mmhealthandfitness Ltd | Wholesale & retail | 2013 |
| MNB Connect Limited | Education | 2021 |
| MNK Alternatives Ltd | Arts & recreation | 2012 |
| MNR Motors Limited | Other services | 2023 |
| MO Fruit & VEG Ltd | Wholesale & retail | 2023 |
| MOA Technology Limited | Professional & scientific | 2017 |
| Mobeka Care Ltd | Health & social care | 2019 |
| Mobile Auto Electrical Services Limited | Wholesale & retail | 2004 |
| Mobile Genie Limited | Information & communication | 2017 |
| Mobile Health MOT Limited | Extraterritorial | 2007 |
| Mobile Mechanic & Tyres Service Oxford Ltd | Wholesale & retail | 2025 |
| Mobile Silent Disco Ltd | Hospitality | 2025 |
| Mobile Tyres Oxford Ltd | Wholesale & retail | 2026 |
| Mobiles for ALL Ltd | Wholesale & retail | 2026 |
| Moda Kitchen Ltd | Manufacturing | 2026 |
| Modad Enterprises Ltd | Information & communication | 2022 |
| Modality Digital Ltd | Information & communication | 2024 |
| Model Boathouse Ltd | Wholesale & retail | 2015 |
| Model HEALTHCARE74 Limited | Wholesale & retail | 2021 |
| Model Pharm Limited | Wholesale & retail | 2021 |
| Modern Art Oxford Limited | Professional & scientific | 2026 |
| Modern Baker Ltd | Manufacturing | 2013 |
| Modern Flow Ltd | Wholesale & retail | 2020 |
| Modern Foundry Limited | Wholesale & retail | 2025 |
| Modern Living Properties 2 Limited | Real estate | 2026 |
| Modern Living Properties Limited | Real estate | 2005 |
| Modern Poetry in Translation Limited | Information & communication | 2006 |
| Modernista Ltd | Hospitality | 2026 |
| Mogford Hotels Limited | Hospitality | 1998 |
| Mogford Limited | Hospitality | 1987 |
| Moghal Ltd | Health & social care | 2015 |
| Mogridge International Holdings Ltd | Professional & scientific | 2025 |
| Mohndis Ltd | Transport & logistics | 2025 |
| Mojisola Dashen Limited | Health & social care | 2022 |
| Mojjo Design Limited | Information & communication | 2014 |
| MOK Properties Oxford Ltd | Real estate | 2014 |
| Mokoro Limited | Professional & scientific | 1982 |
| Molae Properties Limited | Real estate | 2005 |
| Molecular Warehouse Ltd. | Professional & scientific | 2015 |
| Molloy Empire Limited | Real estate | 2024 |
| Molloy Groundwork Construction Ltd | Administrative & support | 2017 |
| Molloy Property Group Limited | Real estate | 2024 |
| Molynx Holdings Limited | Professional & scientific | 1919 |
| Moment Ltd | Information & communication | 2025 |
| Moments and Motion Limited | Information & communication | 2025 |
| Momentum Social Ltd | Professional & scientific | 2017 |
| Momina Boutique Ltd | Wholesale & retail | 2026 |
| Momos&Nudl Ltd | Hospitality | 2026 |
| Momostationoxford Limited | Hospitality | 2024 |
| Monarch Decorating Limited | Construction | 2025 |
| Monard Electrical Contractors LLP | | 2011 |
| Monchu Creative Ltd | Professional & scientific | 2014 |
| Mondial Services Limited | Education | 2001 |
| Monekko Limited | Extraterritorial | 2007 |
| Money Tipps Limited | Education | 2019 |
| Mongol ID Holdings Ltd | Information & communication | 2023 |
| Monkey Puzzle Trading Ltd | Hospitality | 2022 |
| Monkey's Emporium Limited | Extraterritorial | 2019 |
| Monocom UK Limited | Administrative & support | 2004 |
| Monogroup UK Ltd | Professional & scientific | 2019 |
| Monster Consultants Limited | Information & communication | 2025 |