| Kypsan Ltd | Real estate | 2026 |
| KZ UK Home Improvements Limited | Construction | 2020 |
| L & C Carpentry Limited | Construction | 2009 |
| L & L Photography Ltd | Professional & scientific | 2021 |
| L E H Construction Limited | Construction | 2020 |
| L G Garden Maintenance Ltd | Administrative & support | 2023 |
| L Hardy Brickwork Building Contractor Limited | Construction | 2005 |
| L J Marshall Developments Ltd | Construction | 2024 |
| L J Marshall Services Ltd | Professional & scientific | 2026 |
| L K R Consultants Ltd | Professional & scientific | 2024 |
| L M Ashton Livestock Ltd | Agriculture & fishing | 2024 |
| L&A Decorating Ltd | Construction | 2026 |
| L&C Fusion Motors Limited | Wholesale & retail | 2024 |
| L&H Scaffolding & Rigging Ltd | Information & communication | 2017 |
| L&S Cleaning Ninjas Ltd | Administrative & support | 2024 |
| L.B (Bart's) Ltd | Real estate | 2023 |
| L.B. (Tannery) Ltd | Real estate | 2024 |
| L.B. Elstree Limited | Construction | 2023 |
| L.B. Havant Limited | Real estate | 2023 |
| L.B. Lending Limited | Financial services | 2023 |
| L.D.F Construction Ltd | Construction | 2013 |
| L.E.D Electrical Power Ltd | Construction | 2020 |
| L.J Walker Ltd | Transport & logistics | 2025 |
| L.J.F. Consultancy Limited | Health & social care | 2017 |
| L.J.R Interiors Ltd | Construction | 2009 |
| L.J.R Property Ltd | Real estate | 2012 |
| L.M.N Group Ltd | Information & communication | 2025 |
| L.O Careventures Ltd | Health & social care | 2021 |
| L.P Lighting and Photography Ltd | Administrative & support | 2019 |
| L4 Hounslow Ltd | Hospitality | 2026 |
| LA Groundworks (Bucks) Limited | Construction | 2016 |
| LA Salute Ltd | Hospitality | 2023 |
| LAB90 Ltd | Information & communication | 2023 |
| Laddermat Limited | Wholesale & retail | 2023 |
| Ladleswift Limited | Financial services | 1986 |
| Lady Grey Tea Room Ltd | Hospitality | 2019 |
| Lady Wood Solar Farm Limited | Energy | 2023 |
| Ladybird Luck Ltd | Education | 2025 |
| Ladywell Renovations Ltd | Construction | 2026 |
| Lagom Hottubs Ltd | Wholesale & retail | 2019 |
| Lagom Psychology Consulting Ltd | Professional & scientific | 2022 |
| Laiani G a Silva Ltd | Other services | 2024 |
| Lainate Asset Management Limited | Real estate | 2013 |
| Lajpal Food Ltd | Hospitality | 2026 |
| Lakeside Aesthetics (Bucks) Limited | Other services | 2023 |
| Lakeside Aylesbury Limited | Health & social care | 2023 |
| Lako Consulting Ltd | Information & communication | 2024 |
| Lakshmi Private Finance Ltd | Financial services | 2025 |
| Laksman Ltd | Construction | 2025 |
| LAM Trans Ltd | Transport & logistics | 2016 |
| Lamaskerridge Ltd | Health & social care | 2024 |
| Lamberts Rail Ltd | Construction | 2007 |
| Lamburn Company Limited | Wholesale & retail | 2018 |
| Lamcod Limited | Health & social care | 2024 |
| Lamora Healthcare Ltd | Health & social care | 2018 |
| Lana Lawson Limited | Real estate | 2025 |
| Lanas Limited | Construction | 2007 |
| Land House Investments Ltd | Construction | 2018 |
| Landhive D&D Ltd | Construction | 2026 |
| Landhub Design Ltd | Professional & scientific | 2015 |
| Landy Coffee Limited | Hospitality | 2019 |
| Lane Services Limited | Construction | 2026 |
| LANESRA1127 Limited | Health & social care | 2021 |
| Langdon Digital Ltd | Information & communication | 2026 |
| Langdon Estates (Bishopstone) Ltd | Real estate | 2015 |
| Langdon Estates (the Harrow) Ltd | Hospitality | 2015 |
| Langdon Estates Limited | Real estate | 2013 |
| Langley Oak Properties Ltd | Other services | 2026 |
| Langley Registrars Limited | Professional & scientific | 1980 |
| Langley Trustees Limited | Professional & scientific | 2005 |
| Lanka Naturals Ltd | Wholesale & retail | 2025 |
| Lantern Logistics Ltd | Transport & logistics | 2025 |
| Lardy Cat Limited | Manufacturing | 2011 |
| Lares Advisory and Coaching Limited | Professional & scientific | 2023 |
| Larford Farm Estates Ltd | Hospitality | 2013 |
| Larimar Solutions Ltd | Information & communication | 2022 |
| Larion Trans Limited | Transport & logistics | 2026 |
| Larry Consulting Limited | Construction | 2024 |
| Larry's Auto Limited | Professional & scientific | 2024 |
| Laseinde Limited | Professional & scientific | 2016 |
| Lasered Recordings Limited | Information & communication | 2026 |
| Lashtheticx Ltd | Other services | 2022 |
| Last Frontiers Limited | Administrative & support | 1991 |
| Last Interior Design Ltd | Professional & scientific | 2021 |
| Last November Ltd | Information & communication | 2024 |
| Latimer Court (Aylesbury) Freehold Company Limited | Households | 2006 |
| Launton Ltd | Real estate | 2025 |
| Laurelea Limited | Real estate | 2022 |
| Laurentiu Gheorghe Ltd | Construction | 2019 |
| Lava Bucks Limited | Other services | 2020 |
| Lavender Consulting U.K. Limited | Professional & scientific | 2003 |
| Lavish Travel Ltd | Transport & logistics | 2021 |
| Lawler Duncan Limited | Professional & scientific | 2009 |
| Lawnkeeper (Aylesbury) Limited | Administrative & support | 2014 |
| Lawrence Foster Limited | Construction | 2017 |
| Lawyer in the Making Limited | Professional & scientific | 2015 |
| Layby Farm Limited | Real estate | 2019 |
| Layco Property Services Ltd | Real estate | 2019 |
| LAYER10 Limited | Information & communication | 2022 |
| Lazetto Ltd | Real estate | 2022 |