| Kathryn Rose Consultancy Services Limited | Professional & scientific | 2024 |
| KB MED Billings Limited | Professional & scientific | 2018 |
| KBL Solutions Limited | Extraterritorial | 2018 |
| KBO Electrical & Fire Ltd | Construction | 2025 |
| KD Consultancy Services Ltd | Information & communication | 2024 |
| KDC Food Hygiene Ltd | Administrative & support | 2022 |
| KDS Automotive Limited | Wholesale & retail | 2021 |
| Keeble Container Services Limited | Administrative & support | 2000 |
| Keen Controls Limited | Construction | 2009 |
| Keesource Limited | Administrative & support | 2011 |
| Kehui International Limited | Manufacturing | 2016 |
| Keiths Heating Ltd | Construction | 2019 |
| Kelfee Limited | Information & communication | 2007 |
| Kelly`S Travel Limited | Transport & logistics | 2008 |
| Kelmar Vehicles Limited | Wholesale & retail | 2025 |
| KEM Food & Wine Ltd | Wholesale & retail | 2025 |
| Kendal Bright Spark Ltd | Construction | 2018 |
| Kendall & Sons Limited | Construction | 2009 |
| Kess Services Ltd | Construction | 2015 |
| Key Essentials Limited | Agriculture & fishing | 2013 |
| Key Hideouts Ltd | Real estate | 2025 |
| Keygroom Limited | Hospitality | 2000 |
| Keys Accountancy Limited | Professional & scientific | 2014 |
| Kgap Consulting Limited | Information & communication | 2024 |
| KGR Shopping Parade Management Company Limited | Households | 2005 |
| Khloe Nails Ltd | Other services | 2026 |
| Khunnai Thai Restaurant Limited | Hospitality | 2014 |
| Kiankyle Ltd | Extraterritorial | 2021 |
| Kids Party Finder Limited | Administrative & support | 2018 |
| KIN Advisory Ltd | Real estate | 2026 |
| Kindred Cyber Ltd | Information & communication | 2025 |
| Kinetic Consultancy Solutions Ltd | Professional & scientific | 2008 |
| Kingstreetimages Ltd | Information & communication | 2012 |
| Kirk & Randall Ltd | Construction | 2002 |
| Kitwell Administration Limited | Administrative & support | 2017 |
| Knights Court (Standon) Limited | Households | 1991 |
| KNR Installations Ltd | Construction | 2008 |
| Kongra London Limited | Construction | 2005 |
| Kreativ Type Limited | Information & communication | 2012 |
| Kristian Haig Retail Consultancy Limited | Wholesale & retail | 2024 |
| Krones Consulting Limited | Financial services | 2024 |
| KSE Finance Support Limited | Professional & scientific | 2015 |
| Kuchyn Estate Limited | Construction | 2023 |
| KWS Property Solutions Ltd | Real estate | 2021 |
| L V Services Limited | Administrative & support | 2018 |
| L W J Consultancy UK Limited | Administrative & support | 2018 |
| L&B Slaney Ltd | Wholesale & retail | 2017 |
| L&Pg Limited | Information & communication | 2019 |
| L.Sargent & SON Limited | Agriculture & fishing | 1959 |
| L2A Consultancy Limited | Professional & scientific | 2016 |
| LA Property Developments Ltd | Real estate | 2014 |
| Laboratory Sterilizer Services Limited | Manufacturing | 2013 |
| Landmark General Builders Ltd | Construction | 2012 |
| Landrigan Entertainment Ltd | Arts & recreation | 2022 |
| Langley Construction (Enfield) Limited | Construction | 1999 |
| LAR Traffic Services Limited | Administrative & support | 2001 |
| Largam Limited | Administrative & support | 1995 |
| Larisa Judina Ltd | Manufacturing | 2011 |
| Larry's Machineries Limited | Administrative & support | 2025 |
| Laser Electrical Central Limited | Construction | 2015 |
| Latham Road Industrial Units Management Ltd | Real estate | 2024 |
| Laurelo Limited | Professional & scientific | 2013 |
| Lawbros Prestige Ltd | Wholesale & retail | 2025 |
| Lawbros Services Limited | Construction | 2020 |
| Lawson MAY Limited | Professional & scientific | 2025 |
| LBW Tax and Accountancy Services Limited | Professional & scientific | 2016 |
| LCR Property Services Ltd | Construction | 2020 |
| LD Index Holdings Ltd | Financial services | 2022 |
| LDA Holidays Limited | Hospitality | 2025 |
| LDS Consultancy Ltd | Administrative & support | 2025 |
| Leading Environmental Solutions Ltd | Water & waste | 2020 |
| Leafy Oak Nursery Ltd | Agriculture & fishing | 2019 |
| Leafy Oak Tea Room Ltd | Hospitality | 2019 |
| Leage Limited | Professional & scientific | 2014 |
| Leamax Ltd | Real estate | 2025 |
| Leander Legal Ltd | Professional & scientific | 2020 |
| Leaside Turned Parts Holdings Limited | Extraterritorial | 2011 |
| Lecanora Ltd | Professional & scientific | 2023 |
| LEE Pearse Ltd | Transport & logistics | 2014 |
| Leeview Court Management Limited | Households | 2002 |
| Leggate Advisory Limited | Professional & scientific | 2007 |
| LEK Deng Ltd | Hospitality | 2026 |
| Let's DO Elephant English Ltd | Professional & scientific | 2022 |
| Letboost Ltd | Construction | 2026 |
| Lets NO Regrets Ltd | Real estate | 2014 |
| Leviathan Films Limited | Administrative & support | 1999 |
| Lewis Roofing & Sons Ltd | Construction | 2022 |
| Lewis Stephens Consulting Limited | Professional & scientific | 2024 |
| Lewis Todd Ltd | Information & communication | 2022 |
| LHE Cleaning Company Limited | Administrative & support | 2026 |
| Life in Cache (UK) Limited | Information & communication | 2025 |
| Life in Cache Limited | Information & communication | 2017 |
| Life's Green Pictures Ltd | Arts & recreation | 2019 |
| Liffey Contracts Ltd | Construction | 2018 |
| Liftiqo Ltd | Information & communication | 2025 |
| Light SO Shine Ltd | Health & social care | 2024 |
| Lillyjoe Ltd | Hospitality | 2018 |
| Lilstone Limited | Construction | 1997 |
| Lily Girton UK Ltd | Real estate | 2022 |
| Linea EN4 Ltd | Real estate | 2017 |