| Miller Clinical Consultancy Ltd | Professional & scientific | 2013 |
| Millie & BOO Ltd | Wholesale & retail | 2018 |
| Milpa Totnes Ltd | Wholesale & retail | 2026 |
| Mind Over Monkey Ltd | Professional & scientific | 2018 |
| Minxies Ltd | Extraterritorial | 2015 |
| Mlungu Devon Limited | Health & social care | 2025 |
| Mobile Press Limited | Information & communication | 2023 |
| Modelworks.Co.Uk Limited | Wholesale & retail | 2005 |
| Modern Electrical Solutions (SW) Limited | Construction | 2021 |
| Modern Heating and Cooling Solutions Ltd | Energy | 2014 |
| Modern Renewable Solutions Limited | Construction | 2023 |
| Mokki Installations Ltd | Construction | 2024 |
| Mole Valley Sales | Real estate | 1997 |
| Monkey's PAW Consultancy Limited | Professional & scientific | 2014 |
| Monkeyridge Limited | Information & communication | 2007 |
| Montreal Style Bagels Ltd | Manufacturing | 2022 |
| Moonstone Media Ltd | Information & communication | 2009 |
| Moor and Mountain Ltd | Information & communication | 2023 |
| Moor Delivery Services Ltd | Transport & logistics | 2010 |
| Moor to Sea Music Collective CIC | Other services | 2018 |
| Moorganic Ltd. | Financial services | 2023 |
| Moors Consulting Limited | Real estate | 2010 |
| Morellos (Dartmouth) Ltd | Hospitality | 2022 |
| Mossington Limited | Hospitality | 2026 |
| Mount Plym Residents Association Limited | Households | 1989 |
| Mountain Exchange Limited | Financial services | 2012 |
| Moveable Type Theatre Company Ltd | Arts & recreation | 2024 |
| Moved to Move Ltd | Arts & recreation | 2025 |
| Movement Ecology Collective CIC | Education | 2023 |
| MT Cloud Ltd | Information & communication | 2024 |
| Murch & Baker Heating Limited | Construction | 2004 |
| Mushinnoise Ltd. | Information & communication | 2020 |
| My Baby Book Shop Ltd | Wholesale & retail | 2025 |
| Naomi Robertson Ltd | Education | 2025 |
| Narrative Ventures Ltd | Information & communication | 2026 |
| Natural History Book Service Ltd. | Wholesale & retail | 1996 |
| Nature Nurseries Ltd | Education | 2023 |
| Nature's Challenge C.I.C. | Education | 2018 |
| Nature's Way (Totnes) Limited | Wholesale & retail | 2018 |
| Nautical Rose Ltd | Professional & scientific | 2024 |
| Navigate Cooperative Ltd | Education | 2004 |
| NDP Circus Productions Ltd | Hospitality | 2019 |
| Network of Wellbeing | Education | 1984 |
| New Magenta Ltd | Construction | 2020 |
| New Purple Limited | Agriculture & fishing | 2015 |
| New Rumleigh Ltd | Professional & scientific | 1998 |
| New Wood (Holdings) Limited | Professional & scientific | 2009 |
| New Wood Trees Limited | Agriculture & fishing | 2007 |
| Newbury Container Storage Limited | Administrative & support | 2000 |
| Newtons Theory Ltd | Professional & scientific | 2020 |
| Next Word Ltd | Wholesale & retail | 2025 |
| Nhbs Ltd. | Manufacturing | 1985 |
| Nice Four Limited | Information & communication | 2024 |
| Nice Group (SW) Limited | Financial services | 2019 |
| Nice Group One Limited | Information & communication | 2019 |
| Nice Three Limited | Information & communication | 2019 |
| Nice Two Limited | Information & communication | 2018 |
| Nicholas Rowell Haulage Limited | Transport & logistics | 2011 |
| Nigel Irens Design Limited | Professional & scientific | 2010 |
| NJD Wealth Management Limited | Financial services | 2018 |
| Nkuku Limited | Wholesale & retail | 2002 |
| Noori Asset Management Limited | Real estate | 2017 |
| Norbury Weir Limited | Energy | 2014 |
| Norhill Building Limited | Construction | 1997 |
| Nosnevets Limited | Professional & scientific | 2023 |
| NOT Applicable Limited | Real estate | 2011 |
| Nourishing Families CIC | Hospitality | 2019 |
| Nugen Glass Ltd | Manufacturing | 2023 |
| Nutty About Hosting Ltd | Information & communication | 2012 |
| O'Brien Consultancy (SW) Limited | Professional & scientific | 2021 |
| O'Brien Fore Street Limited | Wholesale & retail | 2007 |
| O'Brien Holdings (Devon) Limited | Financial services | 2007 |
| O'Brien Limited | Wholesale & retail | 1995 |
| Oakwood Denbury Ltd | Education | 2008 |
| Ocean Property Group Ltd | Real estate | 2019 |
| OH4 Limited | Manufacturing | 2019 |
| OLA Chiropractic Limited | Health & social care | 2019 |
| Old Mill (Harbertonford) Management Limited | Real estate | 1998 |
| Old School (Totnes) Development and Management Company Limited(The) | Real estate | 1983 |
| Oldbury Court Management Limited | Real estate | 2009 |
| Oldstone Farm Ltd | Wholesale & retail | 2024 |
| Oliver's Butchers & PIE Makers Limited | Wholesale & retail | 2025 |
| Omni Access Ltd | Wholesale & retail | 2017 |
| Omni World Ltd | Hospitality | 2024 |
| One & Eight Ltd | Wholesale & retail | 2016 |
| One Rock Environmental Ltd | Professional & scientific | 2025 |
| Online Counselling Ltd | Health & social care | 2025 |
| Online E Recruitment Limited | Administrative & support | 2000 |
| Ooooby UK Limited | Wholesale & retail | 2016 |
| Operation Friendship Ltd | Health & social care | 2016 |
| Operation Friendship TOO Ltd | Health & social care | 2022 |
| Opop C.I.C. | Hospitality | 2020 |
| Optima LOW Vision Services Limited | Wholesale & retail | 2000 |
| Optimise Devon Ltd | Information & communication | 2020 |
| Opus Alpha Ltd | Professional & scientific | 2025 |
| Orchard House (Dartington) Management Company Limited | Households | 1992 |
| Orestone Services Limited | Administrative & support | 2000 |
| Organic Dyes UK Ltd | Wholesale & retail | 2025 |
| OUT of the Valley Ltd | Manufacturing | 2018 |
| Outdraw Limited | Arts & recreation | 2014 |