| Lias Lettings Limited | Households | 2021 |
| Light Revolution Limited | Manufacturing | 2015 |
| Lighthouse Law Limited | Administrative & support | 2015 |
| Lilliput Textiles Limited | Wholesale & retail | 1999 |
| Lilux Developments Limited | Construction | 2022 |
| Linkflex Industral Co., Ltd | Administrative & support | 2021 |
| Little Toller Books Ltd | Manufacturing | 2012 |
| Livingstone Textiles & Co Ltd | Wholesale & retail | 2026 |
| Livingstone Textiles Company (Bridport) Limited | Wholesale & retail | 2010 |
| LMM Automotive Ltd | Professional & scientific | 2019 |
| LMP Groundwork’S Ltd | Construction | 2022 |
| Lollipop Publishing Limited | Information & communication | 1998 |
| London & Liberty Ltd | Hospitality | 2019 |
| Loofi Ltd | Wholesale & retail | 2025 |
| Loupe Films Limited | Information & communication | 2019 |
| Lovegrove Essentials Ltd | Health & social care | 2015 |
| Luke J Richards Construction Ltd | Construction | 2014 |
| Lulu Consulting Limited | Professional & scientific | 2009 |
| Lunasol Limited | Agriculture & fishing | 1997 |
| Luttrell House Management Company Limited | Households | 1992 |
| Lutze Life Limited | Hospitality | 2016 |
| Luxury Pet Supplies Ltd | Manufacturing | 2016 |
| Lyme 1 Hotel Ltd | Hospitality | 2020 |
| Lyme Bay Lets Ltd | Real estate | 2026 |
| Lyme Bay Ribs Limited | Transport & logistics | 2009 |
| Lyme Management Company Limited | Households | 1993 |
| M & J Cole Ltd | Hospitality | 2024 |
| M&M Land Limited | Construction | 2016 |
| M95 Dorchester Limited | Hospitality | 2024 |
| M95 Holdings Ltd | Financial services | 2021 |
| M95 Lymington Ltd | Hospitality | 2023 |
| M95 Property Investment Ltd | Real estate | 2020 |
| Malcolm Dommett Electrical Ltd | Construction | 2020 |
| Manor Farm Residents Association Walditch Limited | Other services | 1980 |
| Mansbridge Construction and Developments Ltd | Construction | 2018 |
| Maria's Pantry Limited | Hospitality | 2014 |
| Mark Hughes Flooring (Dorset) Limited | Construction | 2013 |
| Mark Lane Water Consultancy Limited | Professional & scientific | 2013 |
| Mark Oborn Limited | Information & communication | 2009 |
| Marley Jacob and Bobb Ltd | Wholesale & retail | 2026 |
| Marshwood Garage Ltd | Wholesale & retail | 2025 |
| Mashayel Limited | Professional & scientific | 2019 |
| Massif Ltd | Wholesale & retail | 2019 |
| Mastoni Tax Limited | Professional & scientific | 2015 |
| Matchbox Conversions Ltd | Manufacturing | 2024 |
| Mateo Kitchen Ltd | Hospitality | 2020 |
| Mattelle NET Limited | Manufacturing | 2003 |
| Matthew Kingston Music Limited | Arts & recreation | 2017 |
| MAY Properties (Dorset) Ltd | Real estate | 2025 |
| Mays Floorplans Limited | Professional & scientific | 2004 |
| MB Cabinet Makers Ltd | Manufacturing | 2014 |
| Meadow Barn Care Farm Ltd | Education | 2024 |
| Meadowsweet Retreat Ltd | Hospitality | 2022 |
| Mektek UK Ltd | Manufacturing | 2002 |
| Meldi MAA Krupa Ltd | Wholesale & retail | 2026 |
| Mell&Co. Ltd | Wholesale & retail | 2021 |
| Melplash Agricultural Society Limited | Administrative & support | 2008 |
| Meraki Collective Ltd | Professional & scientific | 2022 |
| Mercato Italiano Limited | Administrative & support | 2014 |
| Mercato Pronto! Ltd | Administrative & support | 2025 |
| Merge News Limited | Information & communication | 2024 |
| MGL Bookkeeping Limited | Professional & scientific | 2017 |
| MH25 Ltd | Hospitality | 2025 |
| Millie's Yurts Ltd | Manufacturing | 2017 |
| Mindful Digital Collective CIC | Education | 2025 |
| Mira Flores (West Bay) Ltd | Real estate | 2021 |
| MM Blackheath Development Ltd | Construction | 2025 |
| Mmsc Properties Ltd | Real estate | 2021 |
| Modarc Homes Limited | Construction | 2023 |
| Monkton Wyld Farm Limited | Manufacturing | 2004 |
| Monkton Wyld Trading Company Limited | Wholesale & retail | 1991 |
| Montrose Management Company (Bridport) Limited | Households | 1989 |
| Moor Cunningham ELT Limited | Arts & recreation | 2010 |
| Moorbath Time Ltd. | Administrative & support | 2011 |
| More Marketing Limited | Professional & scientific | 2012 |
| Morey Diesel Services Limited | Wholesale & retail | 2003 |
| Mortgage Concepts Commercial Limited | Financial services | 2016 |
| Moss Motor Repairs Limited | Wholesale & retail | 2014 |
| Motorcare (Bridport) Ltd | Wholesale & retail | 2013 |
| Mrjoe Ltd | Information & communication | 2015 |
| MS Building Maintenance Ltd | Construction | 2025 |
| MTD Consulting Ltd | Professional & scientific | 2025 |
| Muffet Ltd | Real estate | 2009 |
| Mumdadandbaby Limited | Wholesale & retail | 2014 |
| My Secret Stay Ltd | Hospitality | 2025 |
| Mystic Limited | Manufacturing | 1983 |
| N J Rawlings & SON Ltd | Construction | 2010 |
| N. Nunn Builders Limited | Construction | 2008 |
| Nadia Essa Limited | Health & social care | 2017 |
| Nantes Solicitors Limited | Professional & scientific | 2010 |
| Nantes Trustees Ltd | Professional & scientific | 2020 |
| Natural Skincare Solutions Ltd | Manufacturing | 2009 |
| Naydon Riding School Limited | Other services | 2015 |
| NET Zero Consultants Limited | Professional & scientific | 2020 |
| New Action Limited | Professional & scientific | 2015 |
| New Inn Shipton Gorge Limited | Hospitality | 2019 |
| New Inn Support Limited | Hospitality | 2006 |
| New Style Bridport Ltd | Other services | 2024 |
| New Vellum Limited | Information & communication | 2011 |
| New Zealand Farm Close Management Ltd | Other services | 2012 |