| Long Marston Village Hall Community Hub CIC | Administrative & support | 2021 |
| Long Ridge Gardens Management Company Limited | Households | 2006 |
| Longbridge Place (Longbridge) Management Company Limited | Real estate | 2018 |
| Longfield Limited | Information & communication | 1994 |
| Longford Lettings Limited | Real estate | 2024 |
| Longs Accountancy Ltd | Professional & scientific | 2025 |
| Longshoot Properties Limited | Real estate | 2002 |
| Loong Noodle Ltd | Hospitality | 2024 |
| Loopy Scoops Limited | Hospitality | 2021 |
| Loose Birds (Harome) Ltd. | Agriculture & fishing | 2000 |
| Lordsmoor Properties Limited | Real estate | 1963 |
| Lork ( Yorkshire ) Ltd | Professional & scientific | 2024 |
| Lork Ltd | Professional & scientific | 2020 |
| Lornarosheen Ltd | Hospitality | 2018 |
| Lorraine Airth Ltd | Other services | 2013 |
| Lorraine Ellison Ltd | Professional & scientific | 2004 |
| Lost in the Woods Limited | Information & communication | 2022 |
| Lottery Field Ltd | Real estate | 2023 |
| Louey Climate & Maintenance Services Ltd | Construction | 2026 |
| Louie Louie Ltd. | Wholesale & retail | 2019 |
| Louise Loves Hair Ltd | Other services | 2018 |
| Loulou Land Ltd | Wholesale & retail | 2022 |
| Loumax Engineering Solutions Ltd | Professional & scientific | 2019 |
| Loup Services Limited | Wholesale & retail | 2009 |
| Lourdas Ltd | Other services | 2026 |
| Love & Last Ltd | Arts & recreation | 2023 |
| Love Cheese Ltd | Wholesale & retail | 2022 |
| Love Your Face Limited | Administrative & support | 2008 |
| Loveday Advisory Ltd | Wholesale & retail | 2025 |
| Lovesbeautyyork Ltd | Other services | 2022 |
| Lovetherapyretreats Ltd | Health & social care | 2026 |
| Lovewish Limited | Information & communication | 2021 |
| LOW Barn Properties Limited | Hospitality | 2016 |
| LOW Greenfield Management Company Limited | Households | 2001 |
| LOW Maintenance Limited | Extraterritorial | 2005 |
| LOW Mill Fold Addingham Management Company Limited | Households | 2006 |
| LOW Moor Agri. Services Limited | Construction | 2024 |
| LOW Windlebeck Limited | Agriculture & fishing | 2020 |
| Lowcross Associates Limited | Wholesale & retail | 2016 |
| Lowen BRE Truro Management Company Limited | Households | 2011 |
| Lowfield Estates (Newett Anlaby) Ltd | Real estate | 2020 |
| Lowther Aluminium Systems Limited | Manufacturing | 2014 |
| Lowther Plumbing & Heating Ltd | Construction | 2025 |
| Lowther Street Cardiac Ltd | Professional & scientific | 2022 |
| Lowther Street Flats Limited | Households | 2011 |
| Lowton Engineering (York) Limited | Manufacturing | 2003 |
| Lowtree Limited | Real estate | 2023 |
| Loxley Design Ltd | Professional & scientific | 2024 |
| Loyd Raynott LP | | 2018 |
| LPA Legal Ltd | Professional & scientific | 2025 |
| LPM Risk Services Ltd | Financial services | 2020 |
| LPM Truck Parts Limited | Wholesale & retail | 2020 |
| LR Accounting Services Limited | Professional & scientific | 2007 |
| LR Diamond Ltd | Manufacturing | 2022 |
| Lr-Refurb Ltd | Wholesale & retail | 2017 |
| Lrfisher & Sons Ltd | Administrative & support | 2024 |
| LRG Property Acquisitions Ltd | Real estate | 2018 |
| LRP Lettings Ltd | Real estate | 2023 |
| LRS Brickwork Ltd | Construction | 2022 |
| LRS Holdings Limited | Professional & scientific | 1994 |
| LS6 Properties Limited | Real estate | 2005 |
| LSL Land & New Homes Ltd | Real estate | 2014 |
| LSQ Concrete Products Ltd | Manufacturing | 2025 |
| LSQ Garden Landscape Ltd | Administrative & support | 2019 |
| Lsvn Limited | Education | 2016 |
| LT Showjumping Limited | Agriculture & fishing | 2024 |
| LT Tax Services Limited | Professional & scientific | 2010 |
| LT Trees and Landscapes Ltd | Administrative & support | 2019 |
| LT Trees Ltd | Agriculture & fishing | 2023 |
| LTT Analytics Ltd | Information & communication | 2023 |
| Lucas Russell Investments Ltd | Real estate | 2026 |
| Lucca Perla Limited | Wholesale & retail | 2019 |
| Lucent Drinks Ltd | Manufacturing | 2018 |
| Lucius Books Limited | Professional & scientific | 2016 |
| Lucknam Crescent (Swindon) Management Company Limited | Households | 2020 |
| Lucky Capital Property Group Ltd | Real estate | 2026 |
| Lucky Days Enterprise Ltd | Hospitality | 2012 |
| Lucky Lian Ltd | Hospitality | 2024 |
| Lucky Table Media Ltd | Information & communication | 2024 |
| Lucolena Limited | Real estate | 2018 |
| Lucoro Limited | Manufacturing | 2013 |
| Ludhill Limited | Professional & scientific | 1998 |
| Ludus Football Group Ltd | Education | 2026 |
| Ludwik's Limited | Other services | 2001 |
| Luke Broadbent Limited | Information & communication | 2013 |
| Luke NDT (EU) Ltd | Wholesale & retail | 2015 |
| Lullex UK Ltd. | Health & social care | 2021 |
| Lumen Controls Ltd | Wholesale & retail | 2025 |
| Lumen Loom Ltd | Wholesale & retail | 2018 |
| Lumiflex Controls Ltd | Wholesale & retail | 2025 |
| Lumin Labs Ltd | Professional & scientific | 2026 |
| Lumina Europa Ltd | Wholesale & retail | 2024 |
| Luminary Communications and Coaching Limited | Professional & scientific | 2021 |
| Luminor Consultancy Limited | Real estate | 2012 |
| Luminor Consulting Solutions Limited | Information & communication | 2018 |
| Luminor Property Management Limited | Real estate | 2017 |
| Luminosa Services Limited | Administrative & support | 2024 |
| Lumitec AI Ltd | Information & communication | 2025 |
| Lumkin Ltd | Arts & recreation | 2026 |
| Luna Resin Wood Art Ltd | Manufacturing | 2024 |