| Keptcastle Limited | Real estate | 1985 |
| Keyfonics Limited | Information & communication | 2007 |
| KF Meps Developments Ltd | Real estate | 2025 |
| Killamarsh Tarmacadam Limited | Professional & scientific | 2008 |
| Kimberworth Insurance Bureau Limited | Financial services | 2003 |
| Kingswood Hall Management Company Limited | Households | 2003 |
| Kirsopp Building Contractors Limited | Real estate | 2006 |
| Kitsons Group Limited | Construction | 2003 |
| KPT Brands Limited | Wholesale & retail | 2006 |
| Kreativ Web Solutions Limited | Information & communication | 2020 |
| Kris Roberts Ltd | Construction | 2007 |
| L & L Enterprises Limited | Real estate | 2002 |
| L + P Mullen Construction Limited | Construction | 2019 |
| L. Roberts (Plumbing and Heating Services) Limited | Construction | 1985 |
| L.G.Construction Limited | Construction | 2003 |
| L.J.C. Roofing Services Ltd | Construction | 2006 |
| Laminated Timber Structures Limited | Construction | 2002 |
| Landmark Surveys (UK) Limited | Construction | 2003 |
| Langdale Court (Barnsley) Limited | Real estate | 2003 |
| Langwith Residential and Nursing Homes Limited | Hospitality | 1988 |
| Lazarus Properties Limited | Real estate | 1997 |
| LE BON VIN Limited | Wholesale & retail | 2000 |
| Leeds Apartments Limited | Real estate | 2000 |
| Leisure Time Sunbeds Limited | Manufacturing | 1992 |
| Leslie Frances (Training) Limited | Extraterritorial | 2005 |
| Letterperfect Limited | Arts & recreation | 1990 |
| Lewis & Towers Limited | Manufacturing | 1920 |
| LGP Realisations Limited | Manufacturing | 1956 |
| Lidgate Management Limited | Real estate | 1995 |
| Liftrucks Northern Ltd | Manufacturing | 2008 |
| Lindsay Financial Services Ltd | Financial services | 2000 |
| Little Angels Nursery PRE School (Yorkshire) Limited | Education | 2003 |
| Little Jo's Day Nursery Ltd | Education | 2002 |
| LL Travel Limited | Transport & logistics | 2004 |
| Logo Leisurewear Limited | Wholesale & retail | 2005 |
| Lomas Engineering Limited | Manufacturing | 1978 |
| Long Flight Limited | Wholesale & retail | 2003 |
| LSO Architects Ltd | Professional & scientific | 2001 |
| Lucas Developments (S & a) Limited | Real estate | 2007 |
| Lysmed Lifestyle Retreats CIC | Hospitality | 2025 |
| M & a Properties Limited | Real estate | 2005 |
| M & N Leisure Limited | Hospitality | 2000 |
| M a H & Sons Limited | Professional & scientific | 2007 |
| M C Thorpe Limited | Professional & scientific | 2008 |
| M.C Furnaces Limited | Manufacturing | 1998 |
| M3 Lettings Limited | Real estate | 2006 |
| Machineco Limited | Manufacturing | 2004 |
| Magnetic Systems Limited | Manufacturing | 1994 |
| Maltby Auto Electrical Services Limited | Manufacturing | 1968 |
| Manor Development Company (Alison Centre) Limited | Administrative & support | 1998 |
| Marbill Rallying Limited | Arts & recreation | 2001 |
| Mark Crapper Photography Limited | Professional & scientific | 2003 |
| Marr Grange (Pork Supplies) Limited | Wholesale & retail | 1988 |
| Marsdens Developments Limited | Real estate | 2001 |
| Martin Johnson Opticians Limited | Health & social care | 2004 |
| Maynards of Westwick Limited | Wholesale & retail | 2007 |
| Mcavoy & Beardsmore Limited | Wholesale & retail | 2005 |
| Mccalls SP Limited | Manufacturing | 1996 |
| Media Services (Yorkshire) Limited | Professional & scientific | 2003 |
| Meljon (Properties) Limited | Real estate | 1978 |
| Melody Retail Ltd. | Wholesale & retail | 1999 |
| Metcru Limited | Wholesale & retail | 1995 |
| Micon Components Limited | Manufacturing | 1974 |
| Mills Property Group Limited | Real estate | 2007 |
| Milvill Limited | Professional & scientific | 2005 |
| Misscues Limited | Arts & recreation | 2006 |
| Mitchell Milne Properties Limited | Real estate | 2000 |
| Mitchell's Vintners Limited | Wholesale & retail | 1999 |
| MNS Mouldings Limited | Manufacturing | 1996 |
| Mobile Hose Services Limited | Other services | 1995 |
| Modest & Co Financial Services Ltd | Professional & scientific | 2004 |
| Mogul Engineers Limited | Manufacturing | 1969 |
| Monaghan Associates Limited | Hospitality | 2003 |
| Monica F. Hewitt Florists Limited | Wholesale & retail | 2004 |
| Moon Climbing Ltd | Manufacturing | 2002 |
| Moorcut Direct Limited | Manufacturing | 1996 |
| Morton Kyle Limited | Professional & scientific | 2003 |
| Mosborough Skips Limited | Water & waste | 2006 |
| Motor Knight Limited | Wholesale & retail | 2018 |
| Mount Medical Services Limited | Real estate | 1994 |
| Mount Pleasant Court Limited | Households | 2006 |
| MPG Property Management Company Ltd | Real estate | 2003 |
| Mtec Services Ltd | Information & communication | 2005 |
| N & Z Enterprises Limited | Real estate | 2000 |
| N G Decor Limited | Administrative & support | 2004 |
| N Stones Builders Limited | Construction | 2003 |
| Napoleons Leisure Group Limited | Extraterritorial | 1995 |
| Napoleons Racing Limited | Professional & scientific | 1995 |
| Nationwide Stainless Limited | Administrative & support | 2000 |
| Navmaf Limited | Real estate | 2022 |
| Neecol Limited | Professional & scientific | 1923 |
| Neepsend Asphalting Limited | Construction | 2003 |
| Neil Parkin Building Limited | Construction | 2005 |
| Nekotronix Ltd | Extraterritorial | 2014 |
| Neon Electrical Limited | Construction | 1999 |
| Network Hydraulics Limited | Manufacturing | 2004 |
| New Divan MAN Limited | Wholesale & retail | 2003 |
| Newtask Electrical Limited | Construction | 2007 |
| Nitroflight Models Limited | Wholesale & retail | 2004 |
| NO Limits Events and Promotions Limited | Administrative & support | 2006 |