| Kestrel Grove Limited | Health & social care | 2022 |
| Kevin & Bros Nails Limited | Other services | 2020 |
| Kforce Consulting Services Ltd | Information & communication | 2024 |
| KFR Construction Ltd | Construction | 2020 |
| KG Care Holdings Limited | Financial services | 2026 |
| KG Care Limited | Financial services | 2022 |
| KHB 18 Limited | Real estate | 2018 |
| Khoki United Limited | Wholesale & retail | 2022 |
| Khyber International (UK) Limited | Administrative & support | 2008 |
| Kick Foods Limited | Manufacturing | 2023 |
| KID City Parties Ltd | Arts & recreation | 2025 |
| Klein Ventures Ltd | Wholesale & retail | 2025 |
| Knight Credit (UK) Ltd | Financial services | 2016 |
| Knight Properties (UK) Ltd | Real estate | 2013 |
| Knights (UK) Ltd. | Construction | 1986 |
| KNN Consultants Limited | Professional & scientific | 2022 |
| Komen Trades Ltd | Wholesale & retail | 2021 |
| Kreative Pace Therapy Ltd | Other services | 2026 |
| Kross Developments Limited | Real estate | 2012 |
| KS Chauhan Properties Ltd | Real estate | 2021 |
| KSS LON Ltd | Real estate | 2025 |
| Kuber Leela Homes Ltd | Real estate | 2021 |
| Kumanan & Enyo NIG Limited | Wholesale & retail | 2025 |
| Kumari Property Development Ltd | Construction | 2024 |
| KVP18 Investments Ltd | Real estate | 2021 |
| KVP9 Investments Ltd | Real estate | 2021 |
| KY Electrical Ltd | Construction | 2019 |
| L & B Stimler Limited | Administrative & support | 1993 |
| L K Beauty & Aesthetics Ltd | Health & social care | 2023 |
| L&D Mortgages Ltd | Financial services | 2016 |
| L. S. Mayer Limited | Extraterritorial | 1967 |
| L.S.E. (Hair & Beauty) Limited | Wholesale & retail | 1992 |
| L.Y. Scaffolding Services Ltd | Construction | 2024 |
| LA LO Enterprise Limited | Wholesale & retail | 2015 |
| LA Lunaria Ltd | Administrative & support | 2025 |
| Labour Numbers Ltd | Construction | 2024 |
| Ladywell Trading Ltd | Wholesale & retail | 2025 |
| Lahore Milton Keynes Limited | Hospitality | 2025 |
| Lahori Flames Limited | Hospitality | 2016 |
| Lahori Flames TM Limited | Other services | 2023 |
| Laith and Wells Ltd | Manufacturing | 2019 |
| Lake Drive Investments Elstree Limited | Real estate | 2024 |
| Lake Drive Investments Ltd | Real estate | 2023 |
| Lake Laurino Management Limited | Households | 1988 |
| Lambda Property Limited | Real estate | 2023 |
| Lambert Metals Properties Ltd | Real estate | 2025 |
| Landmark Homes (UK) Ltd | Administrative & support | 2007 |
| Lanes Consultancy Limited | Professional & scientific | 2020 |
| Langford's Gardening Services Ltd | Administrative & support | 2016 |
| Langstone Properties (LON) Ltd | Administrative & support | 2013 |
| Larchwell Management Ltd | Real estate | 2013 |
| Larfoot Developments Limited | Construction | 2018 |
| Lata Properties Ltd | Real estate | 2020 |
| Latin Soul Dance & Fitness Limited | Arts & recreation | 2010 |
| Latitude IT Limited | Information & communication | 1997 |
| Laughingbull Limited | Administrative & support | 2024 |
| Lavender Legal Enterprises Limited | Professional & scientific | 2017 |
| Lavender RTM Company Limited | Extraterritorial | 2026 |
| Layfair Limited | Wholesale & retail | 2023 |
| LB Construction Group Ltd | Construction | 2025 |
| LBH Holdings Ltd | Real estate | 2019 |
| Lcbi Limited | Professional & scientific | 2015 |
| Lead Hunt Marketing Ltd | Professional & scientific | 2022 |
| Leappro Limited | Construction | 2019 |
| Lears International Limited | Wholesale & retail | 2003 |
| Legacy Innovations Ltd | Information & communication | 2024 |
| Leighton Laine Ltd | Real estate | 2022 |
| Leisurestyle London Limited | Hospitality | 2003 |
| LEO Entertainment Ltd | Administrative & support | 2005 |
| Leon Builders Ltd | Construction | 2020 |
| Lets Protect UK Media Limited | Administrative & support | 2022 |
| LEX Light Limited | Wholesale & retail | 2024 |
| Liam Doran Motor Sports Ltd | Manufacturing | 2010 |
| Libertas Associates Limited | Financial services | 2010 |
| Lifted Facial Aesthetics Ltd | Health & social care | 2025 |
| Light UP Letters Limited | Administrative & support | 2016 |
| Lilian Ajatiton Ltd | Hospitality | 2023 |
| Liligelb Limited | Professional & scientific | 2023 |
| Lime RTM Company Limited | Extraterritorial | 2026 |
| Lime Tree Property (Derby) Ltd | Real estate | 2013 |
| Limpride Ltd | Households | 2023 |
| Lincolnsfields Centre Limited(The) | Health & social care | 1987 |
| Lincolnsfields Playzone Limited | Hospitality | 2020 |
| Lindrop Property Company Limited | Extraterritorial | 1960 |
| Links Private Limited | Real estate | 2022 |
| Linnet Close Ltd | Households | 2020 |
| Liquid Wrap Ltd | Wholesale & retail | 2016 |
| Little 15 Art Limited | Professional & scientific | 2022 |
| Little 15 Investments Limited | Financial services | 2021 |
| Little Acorns Montessori School Limited | Education | 2005 |
| Little Anar Limited | Hospitality | 2025 |
| Livelykicks Ltd | Education | 2021 |
| Liviu AS Ltd | Construction | 2013 |
| LJ Graphic Design Ltd | Professional & scientific | 2025 |
| LJ121 Private Football Coaching Ltd | Education | 2025 |
| LJD Barbering Ltd | Other services | 2025 |
| Ljlr Holdings Ltd | Real estate | 2020 |
| LK Properties & Developments Ltd | Real estate | 2026 |
| LMR Builders (Bushey) Limited | Construction | 2004 |
| LNC Law Limited | Professional & scientific | 2025 |