| Keseray Ltd | Information & communication | 2008 |
| Kettan Foods Limited | Hospitality | 2024 |
| Kevi Corporate Trustee Limited | Hospitality | 2016 |
| Kevin Cordall Limited | Other services | 2003 |
| Keylight P.D.C Limited | Construction | 2014 |
| KGS Veterinary Services Limited | Professional & scientific | 2022 |
| Kian Design UK Ltd | Manufacturing | 2019 |
| Kickles PV Ltd | Energy | 2014 |
| Kildare Project Management Limited | Administrative & support | 2023 |
| Kilncourt Developments Limited | Professional & scientific | 2002 |
| Kiloa Ltd | Professional & scientific | 2014 |
| KIM Queen of Clean Limited | Administrative & support | 2021 |
| Kim's Tea Sales Limited | Wholesale & retail | 2002 |
| KIN Associates Limited | Professional & scientific | 2008 |
| Kites Properties Ltd | Real estate | 2024 |
| KK Cleaning Services Limited | Administrative & support | 2017 |
| KMS Extensions Ltd | Construction | 2021 |
| Knott Hall Development Ltd | Construction | 2019 |
| Kopean Investments Ltd | Financial services | 2026 |
| Koshari FM Ltd | Arts & recreation | 2025 |
| Kourentis Align Ltd | Arts & recreation | 2026 |
| Kplr Limited | Real estate | 2004 |
| Kpny London Limited | Hospitality | 2024 |
| Krocker Film Limited | Information & communication | 2019 |
| Krystal Klene Limited | Administrative & support | 2022 |
| KSF Creative Ltd | Professional & scientific | 2021 |
| Kunchiman Chappins Ltd | Real estate | 2024 |
| Kylix UK Limited | Construction | 2004 |
| Kytty Ltd | Administrative & support | 2024 |
| Kyzo Developments Limited | Real estate | 2005 |
| L & S Consulting Limited | Wholesale & retail | 2000 |
| L G Bower Developments Limited | Real estate | 2013 |
| L Greenaway Sterling Ltd | Financial services | 2026 |
| L Manuel Consultancy Limited | Administrative & support | 2024 |
| L.Stock (Wimbish) Limited | Agriculture & fishing | 1961 |
| LA Boite Ltd | Hospitality | 2018 |
| La-Kyalah Limited | Other services | 2018 |
| Labhoo Ltd. | Information & communication | 2008 |
| Laln Designs Limited | Professional & scientific | 2025 |
| Lambert Fire Protection Ltd | Public administration | 2026 |
| Land & County Development Limited | Construction | 2009 |
| Landfield Property Management Limited | Households | 1983 |
| Landmark Commercial Services Ltd | Construction | 2015 |
| Landmark Interiors Limited | Construction | 2004 |
| Landmark QS Ltd | Professional & scientific | 2016 |
| Lands Limited | Professional & scientific | 2007 |
| Langley Park Rally School Limited | Arts & recreation | 2020 |
| Langthorn Limited | Administrative & support | 2017 |
| Langton Wallis Ltd | Information & communication | 2021 |
| Lanham and Company Limited | Professional & scientific | 1999 |
| Lapin Estates Ltd | Real estate | 2023 |
| Larhar Limited | Transport & logistics | 2020 |
| Lark AV Ltd | Information & communication | 2024 |
| Lark Hall Developments Limited | Construction | 2003 |
| Larl & Bean Limited | Financial services | 2026 |
| Last Friday of the Month Limited | Information & communication | 2014 |
| Latitude 71 Ltd | Other services | 2022 |
| Laundryman Ltd | Administrative & support | 2026 |
| Laura Camp Ltd | Financial services | 2023 |
| Laura Harris Virtual Assistant Ltd | Professional & scientific | 2014 |
| Lavender Fields Management Company Limited | Real estate | 1994 |
| Lavender Jones Recruitment Limited | Administrative & support | 2016 |
| Law Hair Loss Solutions Limited | Other services | 2024 |
| Lazy Two Ltd | Administrative & support | 2016 |
| LBA Carpentry & Home Improvements Ltd | Manufacturing | 2021 |
| LBD Holdco Limited | Administrative & support | 2017 |
| Lbnm Ltd | Hospitality | 2024 |
| LD Landscaping Limited | Administrative & support | 2025 |
| LEA Valley Enterprises Limited | Education | 2014 |
| Leadrboard Ltd | Information & communication | 2026 |
| Leadsforu Ltd | Professional & scientific | 2018 |
| Leaf and Lawn Ltd | Administrative & support | 2017 |
| Leafcutter Films Limited | Information & communication | 2025 |
| Leahill Investments Limited | Financial services | 2020 |
| Leahill Limited | Financial services | 2010 |
| Leasingham Homes (Options) Limited | Households | 2021 |
| Leasingham Homes Limited | Households | 2020 |
| Leefe Ltd | Information & communication | 2025 |
| Legendary Design Limited | Information & communication | 2016 |
| Lemroc Group Ltd | Water & waste | 2023 |
| Lennoch Capital Management LLP | | 2024 |
| Lennoch Ltd | Financial services | 2023 |
| LEO and the Sun Limited | Wholesale & retail | 2022 |
| LEO Electrical Contracting Ltd | Construction | 2019 |
| Leong Capital Holdings Limited | Financial services | 2025 |
| Leong E N T Limited | Health & social care | 2004 |
| Lephyr Limited | Professional & scientific | 2018 |
| Leppards @ Wilderness Farm Limited | Manufacturing | 2021 |
| Lets GET Personalised Co Limited | Wholesale & retail | 2021 |
| Levan Tremain Estates Ltd. | Other services | 2008 |
| Levsy Motor Company Ltd | Wholesale & retail | 2017 |
| Lewis-Wheatley Consulting Ltd. | Professional & scientific | 2025 |
| Lewishall Limited | Hospitality | 2018 |
| Lexfone Communication Inc Ltd | Other services | 2014 |
| Leycam Property Investment Limited | Real estate | 2016 |
| Liberty Dakin Limited | Other services | 2010 |
| Liberty Lane Search Limited | Administrative & support | 2025 |
| Life of Riley (Retail) Limited | Wholesale & retail | 2008 |
| Life Plus Works Ltd | Construction | 2025 |
| Lighthouse Property Rental Ltd | Real estate | 2025 |