| L S Haulage London Ltd | Transport & logistics | 2019 |
| L&P Medics Ltd | Health & social care | 2024 |
| L.I.T Electrical Services Ltd | Construction | 2016 |
| L.L. Bridal Wear Ltd | Manufacturing | 2020 |
| Labour Suppliers 4 U Limited | Construction | 2019 |
| Lagheto Ltd | Hospitality | 2022 |
| Laila Properties Ltd | Real estate | 2016 |
| Laitam Holdings Ltd | Real estate | 2023 |
| Lakay Don's Kitchen Ltd | Manufacturing | 2024 |
| Lambert Heating and Renewables Ltd | Construction | 2013 |
| Lancietrading Ltd | Wholesale & retail | 2023 |
| Landon Decor Ltd | Construction | 2026 |
| Langley Road G & S Ltd | Wholesale & retail | 2022 |
| Launch Contracting Ltd | Construction | 2017 |
| Lavidaprana Limited | Wholesale & retail | 2025 |
| Lavisan Retail Ltd | Wholesale & retail | 2018 |
| Lavish Hair & Beauty London Ltd | Other services | 2020 |
| Lavish Looks Ltd | Other services | 2026 |
| LB Electrical London Ltd | Construction | 2026 |
| Lbautista Care Limited | Health & social care | 2013 |
| LBC Estates Ltd | Real estate | 2016 |
| LBC Property Limited | Real estate | 2019 |
| LBC Services Limited | Professional & scientific | 2022 |
| LBH Lifestyle Ltd | Extraterritorial | 2024 |
| Leading Media Limited | Information & communication | 2018 |
| Leading Surfaces Limited | Construction | 2022 |
| LEARN2LIVE Legacy CIC | Education | 2024 |
| LEE Coach ME Ltd | Arts & recreation | 2022 |
| LEE Savell Properties Limited | Construction | 1989 |
| Leelawadee Thai Massage and Beauty Ltd | Health & social care | 2026 |
| Legents International Education & Migration UK PVT Ltd | Education | 2023 |
| Lelaluchi Limited | Wholesale & retail | 2023 |
| Lelapoochie Limited | Wholesale & retail | 2025 |
| LET Wisdom Guide Limited | Health & social care | 2021 |
| Lewlandii Tree Services Ltd | Administrative & support | 2024 |
| Lexcroft Assets Limited | Real estate | 2025 |
| Lexcroft Developments Limited | Construction | 2015 |
| Lexicon Nippon Ltd | Professional & scientific | 2026 |
| Lifestyle Building Improvements Limited | Construction | 2008 |
| Lightbox Jewellery Limited | Wholesale & retail | 2025 |
| Lighter Works Property Limited | Real estate | 2022 |
| Lighthouse Investments and Finance Limited | Professional & scientific | 1996 |
| Lightning Handyman Services Ltd | Manufacturing | 2020 |
| Link Homes London & Surrey Ltd | Construction | 2018 |
| Linto Builders Ltd | Construction | 2021 |
| Littlebud Bakery Ltd | Manufacturing | 2022 |
| Live Planet Ltd | Wholesale & retail | 2022 |
| Liveworld, Inc. | | 2007 |
| Liviessence Ltd | Manufacturing | 2025 |
| LJB HGV Fleet Services Ltd | Wholesale & retail | 2026 |
| LM Closing Ltd | Wholesale & retail | 2025 |
| Locanda Leone Ltd | Hospitality | 2020 |
| Locokusa Ltd | Wholesale & retail | 2024 |
| Lomi Legal Ltd | Administrative & support | 2013 |
| London Batteries Ltd | Manufacturing | 2025 |
| London Bible Academy | Other services | 2024 |
| London Bike Box Limited | Professional & scientific | 2017 |
| London Bikes Limited | Wholesale & retail | 2026 |
| London Brickwork Ltd | Construction | 2012 |
| London Camera & Antique Auction Ltd | Wholesale & retail | 2025 |
| London CS2 Collegiate Invitational (Lcci) Limited | Information & communication | 2026 |
| London Home Revive Ltd | Construction | 2025 |
| London Maternity and Scan Clinic Ltd | Health & social care | 2024 |
| London Mills Ltd | Wholesale & retail | 2023 |
| London Pipefitting Limited | Construction | 2019 |
| Longlife Fresh Vegetables Ltd | Wholesale & retail | 2026 |
| LOTS2LOVE Ltd | Wholesale & retail | 2020 |
| Lotus Backcare Limited | Health & social care | 2003 |
| Louise Dicrosta Limited | Hospitality | 2024 |
| Love Wills Ltd | Professional & scientific | 2025 |
| Luckybean Tree Limited | Health & social care | 2013 |
| Ludyhairstudios Ltd | Other services | 2026 |
| Lukmanz Food Ltd | Hospitality | 2025 |
| Lulu Montgomerie ENT Limited | Health & social care | 2025 |
| Lumina Support Services (LSS) Ltd | Health & social care | 2025 |
| Lusmore and Lusmore Limited | Construction | 2009 |
| Luxabode Ltd | Real estate | 2020 |
| LVX Design and Build Ltd | Households | 2018 |
| M & B Building Contractors Ltd | Construction | 2024 |
| M & K Properties Surrey Ltd | Real estate | 2017 |
| M & N Butchers Limited | Wholesale & retail | 2017 |
| M & P Best Chicken Ltd | Hospitality | 2018 |
| M Fazal Ltd | Real estate | 2023 |
| M&B Builders Ltd | Construction | 2025 |
| M&J Janowscyl Limited | Real estate | 2024 |
| M25 Groundworks Limited | Construction | 2021 |
| Maadhaa Rakshan's Properties Ltd | Real estate | 2023 |
| Maclachlanwood Ltd | Information & communication | 2021 |
| Made for Real Kings Ltd | Wholesale & retail | 2025 |
| Madet Limited | Wholesale & retail | 2019 |
| Maen Group Ltd | Transport & logistics | 2016 |
| MAG UKR Construction Ltd | Construction | 2020 |
| Magic of Cleaners Limited | Administrative & support | 2016 |
| Mahaaya UK Ltd | Information & communication | 2026 |
| Maidenbower Insulation Limited | Construction | 2002 |
| Maifam and Associates Limited | Wholesale & retail | 2025 |
| Maison D'Etre Limited | Real estate | 2021 |
| Maison Developments & Construction Ltd | Construction | 2016 |
| Maiyear Limited | Administrative & support | 2015 |
| Majek Consultancy Limited | Professional & scientific | 2016 |