| KC Welding Services Ltd | Professional & scientific | 2015 |
| Kdno Shaw Ltd | Real estate | 2025 |
| Kelsey Lewis Brown Property Ltd | Real estate | 2026 |
| Kemp Build Limited | Construction | 2008 |
| KEN Martin Electrical Ltd | Construction | 2009 |
| KEN Wood & Sons (Construction) Limited | Construction | 1991 |
| KEN Wood and Sons (Developments) Limited | Extraterritorial | 2008 |
| Kenyon Engineering Ltd | Other services | 2023 |
| Kern-Liebers Limited | Manufacturing | 1977 |
| Kevin Thornhill Limited | Construction | 2014 |
| Key Electrical Engineers Limited | Construction | 2000 |
| KFR Fabrications Limited | Manufacturing | 2026 |
| Kids Own Physio Limited | Arts & recreation | 2021 |
| Kinch Holdings Ltd | Other services | 2023 |
| Kinetic Health Group Ltd | Health & social care | 2026 |
| Kings' Park Antiques Limited | Wholesale & retail | 2026 |
| Kirby Blythe Specialist Services Ltd | Other services | 2022 |
| Kirk Gregory Ltd | Construction | 2015 |
| Kirton Lindsey Holdings Limited | Financial services | 2019 |
| Kirton Sectional Buildings Limited | Manufacturing | 1995 |
| Kite Glass (Europe) Limited | Manufacturing | 2017 |
| Kixx East Lincolnshire Limited | Education | 2025 |
| Kixx Grimsby Ltd | Extraterritorial | 2017 |
| Kixx Mansfield Limited | Arts & recreation | 2015 |
| Kixx Nottingham Limited | Arts & recreation | 2023 |
| Kixx Rotherham Limited | Arts & recreation | 2023 |
| Kixx West Lindsey Ltd | Education | 2020 |
| KJL Group Holdings Ltd | Financial services | 2026 |
| Knee Surgery Ltd | Health & social care | 2022 |
| Knights Electrocom Limited | Wholesale & retail | 2002 |
| Knowles Plumbing, Heating & Mechanical Services Ltd | Construction | 2025 |
| Kool Cuts Barbers Ltd | Other services | 2025 |
| Korc Sport Ltd | Arts & recreation | 2016 |
| KPB Lettings Limited | Real estate | 2025 |
| KR Educational Psychology Services Ltd | Health & social care | 2026 |
| Kristof Removals Ltd | Transport & logistics | 2013 |
| Kronos Design Limited | Professional & scientific | 2003 |
| KRW Consultancy Limited | Professional & scientific | 2021 |
| Kubed Limited | Manufacturing | 2010 |
| Kyte Digital Ltd | Information & communication | 2020 |
| L & PJ Industries Ltd | Hospitality | 2023 |
| L and L Transport Ltd | Transport & logistics | 2023 |
| L Fahy Services Ltd | Professional & scientific | 2019 |
| L Fletcher Electrical Contractor Ltd | Construction | 2016 |
| L G Bathrooms Ltd | Construction | 2026 |
| L K Electrical Installations Ltd | Construction | 2026 |
| L R Hutchinson Limited | Construction | 2013 |
| L S Legal Services Limited | Professional & scientific | 2024 |
| L&J Developments Gainsborough Ltd | Real estate | 2019 |
| L&J Fitters Limited | Construction | 2014 |
| L&J James Investments Ltd | Hospitality | 2020 |
| L. J Trevor Haulage Limited | Transport & logistics | 2005 |
| L.F.C. Horkstow Limited | Agriculture & fishing | 1972 |
| LA Fontana Gainsborough Ltd | Hospitality | 2026 |
| LAL Developments Ltd | Real estate | 2025 |
| Lambirth Clark Ltd | Professional & scientific | 2021 |
| Land Network (Gainsborough) Limited | Water & waste | 2003 |
| Lanes and Events TMS Ltd | Professional & scientific | 2022 |
| Language Books Ltd | Wholesale & retail | 2005 |
| Larc Services Ltd | Administrative & support | 2022 |
| Laserbeak Cleaning Ltd | Administrative & support | 2025 |
| Laughton Wood Agricultural Limited | Administrative & support | 2009 |
| Laughton Wood Equestrian Centre Ltd | Arts & recreation | 2019 |
| Laurel Bank Services Ltd | Administrative & support | 2018 |
| Laurie Lawless Coaching Ltd | Other services | 2023 |
| LBH & DCS Ltd | Professional & scientific | 2025 |
| Ld&F Limited | Wholesale & retail | 2010 |
| LDM Transport Limited | Transport & logistics | 2015 |
| LEA Consulting 2018 Limited | Professional & scientific | 2018 |
| LEA Distribution Limited | Wholesale & retail | 2020 |
| LEA Property Ltd | Real estate | 2021 |
| LEA Wood Trails and Tails Limited | Other services | 2019 |
| Leadley's Detailing Ltd | Wholesale & retail | 2025 |
| LEE Joinery Ltd | Construction | 2018 |
| Leeder Family Assets Ltd | Professional & scientific | 2026 |
| Legal Funding Agreement Limited | Administrative & support | 2013 |
| Leksmo Ltd | Other services | 2025 |
| Lemon Tree Films Ltd | Information & communication | 2025 |
| Leon's Traditional Fish & Chips Ltd | Hospitality | 2026 |
| Levick Properties Limited | Financial services | 2018 |
| LEW Electrical Distributors Limited | Extraterritorial | 2018 |
| LEW Group Holdings Limited | Financial services | 2022 |
| LEW Renewables Limited | Extraterritorial | 2022 |
| Lewcon Rail Ltd | Construction | 2015 |
| Liam Atkin Racing Limited | Arts & recreation | 2025 |
| Liam Lynch Construction (UK) Ltd | Construction | 2021 |
| Lifespace Homes Limited | Financial services | 2014 |
| Liftsafe Solutions Limited | Manufacturing | 2008 |
| Lightbaze Digital Services Limited | Information & communication | 2023 |
| Lighting Planet Limited | Wholesale & retail | 2014 |
| Limestone Farming Company Limited | Agriculture & fishing | 1936 |
| Linc IT (Gainsborough) Limited | Information & communication | 2001 |
| Lincoln Auto & Performance Ltd | Wholesale & retail | 2022 |
| Lincoln Energy Surveys Ltd | Other services | 2022 |
| Lincoln IMP Bricks - the Brick HUT Limited | Wholesale & retail | 2023 |
| Lincoln Martial Arts & Fitness Ltd | Education | 2024 |
| Lincoln Rowing Centre Limited | Arts & recreation | 2009 |
| Lincoln Stainless Limited | Wholesale & retail | 1991 |
| Lincolnshire Baby Limited | Wholesale & retail | 2026 |
| Lincolnshire Bearings and Fasteners Ltd | Wholesale & retail | 2011 |