| Kids Care Charity | Health & social care | 2013 |
| Kietis Contracts Ltd | Construction | 2026 |
| Kilcoy Chalets Ltd | Hospitality | 2018 |
| Killachu Ltd | Wholesale & retail | 2025 |
| KIM Investments Limited | Real estate | 2019 |
| Kimuk Limited | Wholesale & retail | 2022 |
| Kinetech LAB Ltd | Information & communication | 2017 |
| Kinetic Contractors Ltd | Manufacturing | 2023 |
| Kinetic Synergy Limited | Wholesale & retail | 2023 |
| Kings Humanity Ltd | Health & social care | 2018 |
| Kinnell Court (Sidcup) Management Limited | Households | 1979 |
| Kins Consultancy Limited | Information & communication | 2013 |
| Klim Investments Limited | Real estate | 2020 |
| Klrl Enterprises Ltd | Other services | 2018 |
| Kmkt Holdings Ltd | Financial services | 2025 |
| Knatware Technology Ltd | Information & communication | 2023 |
| KNE Fire Protection Limited | Public administration | 2026 |
| Knight Holdings Limited | Professional & scientific | 2005 |
| Knight Plaster Mouldings Ltd | Manufacturing | 2023 |
| Knightsbridge Plumbers Limited | Construction | 2017 |
| KO Tactical Ltd | Professional & scientific | 2025 |
| Koffi POT Ltd | Administrative & support | 2018 |
| Koleswift Ltd | Wholesale & retail | 2022 |
| Kondeco Ltd | Construction | 2017 |
| Koosan Hospitality Limited | Administrative & support | 2024 |
| Kreative VH Consulting Limited | Information & communication | 2011 |
| Krisah Technologies Ltd | Information & communication | 2020 |
| Krishan Mohan Chanan Ltd | Extraterritorial | 2024 |
| Krism Dwellings Limited | Real estate | 2019 |
| Krism Limited | Information & communication | 2018 |
| Kristal Trading Ltd | Wholesale & retail | 2024 |
| KSD Contractor London Limited | Construction | 2026 |
| KSH Investments Limited | Real estate | 2017 |
| Kuber Holdings Limited | Construction | 2024 |
| Kurbtrading Ltd | Wholesale & retail | 2021 |
| Kurt Education Ltd | Education | 2022 |
| Kusbaybee Ltd | Other services | 2014 |
| Kwahuman Youthman Skills Enterprise Ltd | Health & social care | 2019 |
| KY Plumbing & Heating Ltd | Other services | 2024 |
| Kyeeni Ltd | Wholesale & retail | 2025 |
| Kylanja Limited | Education | 2004 |
| L a Nails Limited | Other services | 2007 |
| L J Shaw Ltd | Professional & scientific | 2017 |
| L M Lift Services Limited | Construction | 2016 |
| L&D Painting and Decorating Ltd | Construction | 2018 |
| L.T International Group Ltd | Wholesale & retail | 2025 |
| L.W.Burt & SON Limited | Construction | 2004 |
| LA Construction Services Ltd | Construction | 2015 |
| Labour Direct Services Limited | Construction | 1997 |
| Laisu BR Limited | Real estate | 2016 |
| Laisu CR Limited | Real estate | 2023 |
| Lakedale Investments Ltd | Construction | 2021 |
| Lakhey International Ltd | Wholesale & retail | 2020 |
| Laksh Consultancy Ltd | Professional & scientific | 2016 |
| Lamhouse Ltd | Administrative & support | 2019 |
| Landlord and Tenant (London) Ltd | Professional & scientific | 2025 |
| Langman Homes Ltd | Real estate | 2025 |
| Laniakea Holdings Limited | Financial services | 2026 |
| Lanzetta Services Limited | Hospitality | 2022 |
| Lara S Solutions Ltd | Administrative & support | 2024 |
| Larchwell Estates Ltd | Construction | 2000 |
| Lawson Icecream Limited | Hospitality | 2020 |
| Layers of Integrity Limited | Construction | 2017 |
| LCC Window Cleaning Ltd | Administrative & support | 2023 |
| Lcon Contractors Ltd | Construction | 2022 |
| LD Fire Solutions Limited | Public administration | 2018 |
| LDM Building Services Kent Ltd | Other services | 2020 |
| LDN Capital Ltd | Professional & scientific | 2024 |
| Leadership Horizons Ltd | Wholesale & retail | 2025 |
| Leading Agile Limited | Information & communication | 2021 |
| Leading Bridges Ltd | Financial services | 2020 |
| Lebano Grill Ltd | Hospitality | 2025 |
| Legacy Artist Ltd | Information & communication | 2026 |
| Legal Link Recruitment Ltd | Administrative & support | 2024 |
| Lenham Consultancy Services Limited | Professional & scientific | 2012 |
| Leon Barber Shop Ltd | Other services | 2020 |
| Lessmedia Limited | Information & communication | 2023 |
| Lesta Projects Limited | Information & communication | 2007 |
| Let's BE Real Limited | Real estate | 2020 |
| Let's Go Scaffolding Ltd | Construction | 2023 |
| Lexcel Limited | Professional & scientific | 2013 |
| LGC Decorators Ltd | Construction | 2014 |
| LI Lina Limited | Hospitality | 2025 |
| Liberatus Consultancy Limited | Administrative & support | 2022 |
| Lift Test Weights Limited | Extraterritorial | 2012 |
| Liftingirons Ltd | Information & communication | 2026 |
| Liks KBF Ltd | Real estate | 2022 |
| LIL Dimsum Ltd | Professional & scientific | 2020 |
| Lilob Ltd | Health & social care | 2014 |
| Lilybe Ltd | Real estate | 2021 |
| Lilys Bouncy Castles & Soft Play Hire Limited | Arts & recreation | 2019 |
| Lily’S Lens Lifestyle Photography Ltd | Professional & scientific | 2021 |
| Linkbuy Limited | Wholesale & retail | 2025 |
| Linnet Theatre Ltd | Arts & recreation | 2023 |
| Linum Ltd | Wholesale & retail | 2023 |
| Lion of Judah Accounting Associate Limited | Professional & scientific | 2013 |
| Lipotherapeia Limited | Other services | 2011 |
| Liquid Entertainment Limited | Administrative & support | 2015 |
| Liquorice Kids Ltd | Wholesale & retail | 2022 |
| Little Green Leaf Ltd | Professional & scientific | 2020 |