| Laura Bateman Investments Limited | Financial services | 2021 |
| Lauren’S Horsebox Hire Ltd | Administrative & support | 2025 |
| Lawn Science Reading Ltd | Administrative & support | 2020 |
| Leading Through Storms CIC | Education | 2021 |
| Leamington Land (Developments) Ltd | Construction | 2012 |
| Leamy Consulting Ltd | Administrative & support | 2024 |
| Leamy Limited | Extraterritorial | 2008 |
| Leighton Studios Limited | Other services | 2023 |
| Lemon Melon Publishing Limited | Information & communication | 2019 |
| LES Deux Barons Ltd | Wholesale & retail | 2017 |
| LEW on SAX Ltd | Arts & recreation | 2023 |
| Lewis Road Investments Limited | Real estate | 2010 |
| LFL Consulting Ltd | Professional & scientific | 2025 |
| Licensing & Safety Lawyers Ltd | Professional & scientific | 2013 |
| Life Assets I L.P. | | 2009 |
| Like Wines Ltd | Wholesale & retail | 2020 |
| Lillingston Limited | Hospitality | 2007 |
| Lindens House Management Company Limited | Households | 2007 |
| Link Electrical Contractors Ltd | Construction | 2013 |
| Lisa Estates (Cobham) Limited | Construction | 2013 |
| Lisa Estates (Delancey) Limited | Construction | 2012 |
| Lisa Estates (East Horsley) Limited | Construction | 2007 |
| Lisa Estates (East Molesey) Ltd | Construction | 2012 |
| Lisa Estates (Isleworth) Limited | Construction | 2014 |
| Lisa Estates (Paragon) Limited | Construction | 2025 |
| Lisa Estates (Storrington) Limited | Construction | 2012 |
| Lisa Estates (Thirlestaine) Limited | Construction | 2013 |
| Lisa Estates (Watlington) Limited | Construction | 2020 |
| Lisa Estates (Wilton Park) Limited | Construction | 2024 |
| Ljconlon Ltd | Professional & scientific | 2025 |
| LMH Tree Services Limited | Administrative & support | 2023 |
| London Estate Limited | Real estate | 2005 |
| Long Future Research Ltd | Professional & scientific | 2022 |
| Longpine Limited | Construction | 2014 |
| Lookfar Ltd | Information & communication | 2022 |
| Lord Street Homes Limited | Real estate | 2022 |
| Lords Fragrance House Ltd | Manufacturing | 2021 |
| Love Life Fitness Limited | Arts & recreation | 2012 |
| Lower Wharf (Management) Limited | Households | 1983 |
| LRC Services (Buckinghamshire) Limited | Wholesale & retail | 2013 |
| LRD Life Limited | Wholesale & retail | 2015 |
| Luan Barci Construction Ltd | Construction | 2023 |
| Lucky Pigeon Limited | Other services | 2022 |
| Luker Lightening Technologies Limited | Professional & scientific | 2010 |
| Luxe Homes Construction Ltd | Construction | 2019 |
| Luxe Homes Design & Build Ltd | Administrative & support | 2017 |
| Luxe Homes Developments Ltd | Construction | 2017 |
| Lymeminster Limited | Professional & scientific | 1986 |
| Lytton & Co.(London)Limited | Wholesale & retail | 1938 |
| M J Conway Ltd | Administrative & support | 2013 |
| M.N Vhanga Ltd | Health & social care | 2016 |
| MAC Architecture Ltd | Construction | 2015 |
| Machine MAX Limited | Professional & scientific | 2018 |
| Mackenzie Landscape Co Oxford Limited | Administrative & support | 2026 |
| Macktech Group Ltd | Construction | 2026 |
| Magazines Plus Limited | Manufacturing | 2006 |
| Mainhouse Productions Ltd | Information & communication | 2024 |
| Maison White Ltd | Wholesale & retail | 2021 |
| Maitland-Smith Holdings Limited | Professional & scientific | 2015 |
| Maitland-Smith Working Capital Limited | Professional & scientific | 2017 |
| MAJ Integration Limited | Other services | 2017 |
| Makin Holdings Ltd | Information & communication | 2023 |
| Makin Properties Limited | Real estate | 2024 |
| Makoro Ltd | Real estate | 2012 |
| Manalytics Ltd | Professional & scientific | 2025 |
| Mango Road Limited | Real estate | 2016 |
| Mani Law Limited | Professional & scientific | 2016 |
| Mann Contractual Management Limited | Professional & scientific | 2017 |
| Manor Gardens (Beechcroft) Limited | Households | 2024 |
| Manor Interiors (Oxfordshire) Limited | Construction | 2019 |
| Manvell Industrial Technologies Limited | Wholesale & retail | 2014 |
| Manvell Product Design Limited | Professional & scientific | 2012 |
| Marceline Boutique CIC | Wholesale & retail | 2024 |
| Marcu Medical Services Limited | Health & social care | 2025 |
| Marketing Resources (UK) Ltd | Other services | 2013 |
| Markey Primary Services Limited | Health & social care | 2010 |
| Markun Enterprises Limited | Wholesale & retail | 2008 |
| Marmalade Hive Ltd | Real estate | 2019 |
| Marmion Property Investments Limited | Real estate | 2025 |
| Marsal Design Ltd | Professional & scientific | 2022 |
| Masterfloors (Wallingford) Limited | Wholesale & retail | 2011 |
| Mathematical Market Research Limited | Information & communication | 1988 |
| Matt Badenoch Photography Limited | Professional & scientific | 2014 |
| Maxpure Windows Ltd | Administrative & support | 2020 |
| Mayfair&Oxford Studio Ltd | Administrative & support | 2026 |
| Maynard Business Management Ltd | Professional & scientific | 2003 |
| MB Datum Limited | Construction | 2024 |
| MBS Event Projects Ltd | Professional & scientific | 2019 |
| Mcaleer Family Investments Limited | Financial services | 2026 |
| Mcaleer Holdings Limited | Health & social care | 2019 |
| Mcardle Sport-Tec Holdings Limited | Financial services | 2018 |
| Mcardle Sport-Tec Limited | Construction | 1999 |
| Mcgregor Investment Management Ltd | Financial services | 2014 |
| MCR Systems Limited | Information & communication | 1978 |
| Meadow Properties (Oxfordshire) Ltd | Real estate | 2024 |
| Meath Consulting Ltd | Professional & scientific | 2019 |
| Media Minds Limited | Professional & scientific | 2017 |
| Medium Cool Limited | Information & communication | 1996 |
| MEG Robson Executive Coaching Ltd | Professional & scientific | 2025 |
| Melma Ltd | Financial services | 2023 |