| KB Agency Services Ltd | Health & social care | 2015 |
| KDC Billinghay Ltd | Construction | 2019 |
| KDC Kipling Close Ltd | Construction | 2017 |
| KDC Mattersey Thorpe Ltd | Construction | 2019 |
| KDC Nether Langwith Ltd | Construction | 2018 |
| KDC Properties Ltd | Construction | 2015 |
| Keen Transport Services Ltd | Transport & logistics | 2025 |
| Keene Health Ltd | Arts & recreation | 2024 |
| Kentalla Ltd | Administrative & support | 2023 |
| Kenyon Property Ltd | Real estate | 2024 |
| Kersa Ltd | Professional & scientific | 2011 |
| Kettlewell Properties Limited | Real estate | 2013 |
| Kev's Carpets Limited | Wholesale & retail | 2007 |
| Kevi (Retford) Block a Freehold Limited | Real estate | 2016 |
| Kevi (Retford) Block B Freehold Limited | Real estate | 2016 |
| Kezi & Clay Healthcare Ltd | Administrative & support | 2021 |
| KFH Trading Ltd | Hospitality | 2018 |
| KG Telecom Consultancy Ltd | Information & communication | 2026 |
| KHS Services Limited | Construction | 2017 |
| Kindways Care Ltd | Health & social care | 2025 |
| King Family Holdings Limited | Wholesale & retail | 2016 |
| Kingdom Statics Ltd | Wholesale & retail | 2020 |
| Kingfisher Direct Limited | Wholesale & retail | 2011 |
| Kingfisher Industrial Developments Limited | Construction | 2022 |
| Kingfisher Industrial Services Ltd | Administrative & support | 2015 |
| Kings Stores Limited | Wholesale & retail | 2008 |
| Kingsgate Nutrition Limited | Wholesale & retail | 2015 |
| Kiss Holdings Limited | Professional & scientific | 2002 |
| KJT Property Maintenance Ltd | Construction | 2025 |
| Knightsbridge Protection Services Ltd | Administrative & support | 2022 |
| Knots Carpentry & Joinery Limited | Manufacturing | 2023 |
| Knowledge Focus Limited | Information & communication | 2001 |
| Kobi Construction Limited | Construction | 2020 |
| KOI Retail Services Limited | Wholesale & retail | 2024 |
| KOI S.O.S. Limited | Wholesale & retail | 2022 |
| Kolekar Properties Limited | Real estate | 2022 |
| KRE8TIVE Limited | Administrative & support | 2018 |
| Krithiks Convenience Stores Ltd | Wholesale & retail | 2024 |
| Kuki Helicopter Sales Ltd | Administrative & support | 2003 |
| KYA Registering Ltd | Professional & scientific | 2026 |
| L & S Richardson Limited | Information & communication | 2025 |
| L Bailey Agricultural Limited | Agriculture & fishing | 2014 |
| L F Taylor Limited | Construction | 2003 |
| L K Griffin Limited | Wholesale & retail | 2011 |
| L.K.Clarke Transport Ltd | Extraterritorial | 2025 |
| L.T Property Lettings Ltd | Real estate | 2018 |
| Ladeca Ltd | Construction | 2019 |
| Lakethorn Builders Limited | Construction | 2005 |
| Laminar Performance Ltd | Manufacturing | 2013 |
| Langley Aviation Limited | Professional & scientific | 2000 |
| Langley Holdings PLC | Professional & scientific | 1977 |
| Laser Scanning Forum Ltd | Information & communication | 2010 |
| LBL Lashes Ltd | Other services | 2022 |
| LBS Pest and Wildlife Solutions Limited | Agriculture & fishing | 2018 |
| LCH Trucks Limited | Wholesale & retail | 2002 |
| LDD Electrical Limited | Construction | 2018 |
| LE Automation Ltd | Construction | 2026 |
| Leaders and Teams Ltd | Professional & scientific | 2019 |
| Leaf Pillows UK Ltd | Manufacturing | 2021 |
| Leaky Teacup Ltd | Hospitality | 2019 |
| Leanne Broadhead Limited | Information & communication | 2008 |
| LEE Brendan Stevens Limited | Extraterritorial | 2025 |
| LEE Sinclair Furniture Limited | Manufacturing | 2003 |
| LEE Stevens Limited | Extraterritorial | 2025 |
| Leela Promotions Limited | Administrative & support | 2015 |
| Leonardos Retford Limited | Other services | 2020 |
| Leritum Limited | Wholesale & retail | 2025 |
| Let's for the Community C.I.C. | Arts & recreation | 2021 |
| Level UP Finance Limited | Extraterritorial | 2025 |
| Level UP Wealth Limited | Extraterritorial | 2025 |
| Leverton & Company Limited | Professional & scientific | 1989 |
| LEX Cosmetics & Training (East Midlands) Limited | Other services | 2022 |
| Life Dental Care Limited | Real estate | 2012 |
| Life Excel (UK) Ltd | Health & social care | 2023 |
| Lifetime Education Limited | Wholesale & retail | 2009 |
| Lifts UK Limited | Manufacturing | 2003 |
| Lignum Sanctum Ltd | Manufacturing | 2025 |
| Lilac Homes Limited | Construction | 2018 |
| Lilleker Bros. (Holdings) Ltd | Financial services | 2020 |
| Lilleker Bros. EOT Ltd | Financial services | 2024 |
| Lilly Contracts Ltd | Construction | 2018 |
| Lily’S Ladies Cleaning Services Ltd | Administrative & support | 2021 |
| Lime Grove (Holdings) Limited | Construction | 2015 |
| Linbax Investments | Financial services | 2017 |
| Lincoln & District Model Engineering Society | Other services | 2013 |
| Linden Surfacing Ltd | Administrative & support | 2023 |
| Linkpark Limited | Real estate | 2003 |
| Linkspeed Couriers Ltd | Transport & logistics | 2024 |
| Little Marshmallow Ltd | Wholesale & retail | 2024 |
| LJS Pictures Limited | Information & communication | 2007 |
| LKC Property Limited | Real estate | 2025 |
| Lkholdings Ltd | Financial services | 2020 |
| LLD Business Services Ltd | Administrative & support | 2023 |
| Lliber Solutions Limited | Professional & scientific | 2020 |
| Loates Bros. Limited | Agriculture & fishing | 1956 |
| Loire Capital Holdings Ltd | Financial services | 2026 |
| London Road Garage (Retford) Limited | Wholesale & retail | 2008 |
| Loop Events Ltd | Administrative & support | 2025 |
| Loose Box Equestrian Limited | Arts & recreation | 2017 |
| Lord Flynn Investments Ltd | Real estate | 2022 |