| Lisburn Music Centre Shop Ltd | Wholesale & retail | 2023 |
| Lisburn Nails & Spa Ltd | Other services | 2023 |
| Lisburn Services Ltd | Construction | 2018 |
| Lisburn Steam Clean Limited | Administrative & support | 2024 |
| Lisburn Travel Clinic Limited | Health & social care | 2003 |
| LISKEB1 Limited | Hospitality | 2025 |
| Lismoyne Holdings Limited | | 1973 |
| Lisnacurran SC Limited | Hospitality | 2019 |
| Lisnatunny Limited | Real estate | 2021 |
| Lissue Enterprises Limited | Agriculture & fishing | 2023 |
| Listo Limited | Manufacturing | 2007 |
| Little India Restaurant Limited | Professional & scientific | 2021 |
| Little Mexican Deli Ltd | Hospitality | 2020 |
| Little Moments NI Ltd | Administrative & support | 2024 |
| Little Panda Belfast Ltd | Hospitality | 2025 |
| Little Panda Limited | Hospitality | 2023 |
| Little Popcorn Shop Ltd | Hospitality | 2025 |
| Little Rays Limited | Administrative & support | 2004 |
| Little Scamps Playgroup & Afterschool Limited | Health & social care | 2018 |
| Little Weavers Day Care Limited | Health & social care | 2025 |
| Living Kerr & Co Ltd | Real estate | 2013 |
| Livinyoun LLP | | 2018 |
| Liweiweihjfvhj Ltd | Wholesale & retail | 2024 |
| Ljuli and Skivi LP | | 2021 |
| LMB Action Entertainment Ltd | Arts & recreation | 2024 |
| LMC Pet Foods Ltd | Wholesale & retail | 2017 |
| LMF Holdings Ltd | Wholesale & retail | 2017 |
| LMI Holdings Limited | Real estate | 1989 |
| LN Takeaway Ltd | Hospitality | 2019 |
| LNC Ecom Limited | Wholesale & retail | 2024 |
| Locksley Mews Management Company Ltd | Households | 2019 |
| Logan Medical Belfast Limited | Other services | 2016 |
| Logiclinecoders Limited | Information & communication | 2025 |
| London Electronics Exchange Limited | Information & communication | 2022 |
| London Irish Rugby Football Club Holdings Ltd | Arts & recreation | 2024 |
| Longstand (N.I.) Limited | Real estate | 2024 |
| Look Events Ltd | Professional & scientific | 2024 |
| Loral Developments Ltd | Construction | 2007 |
| Loren Business LLP | | 2016 |
| Lorna Watters Beauty Ltd | Other services | 2024 |
| Lorraine Laird Ltd | Agriculture & fishing | 2023 |
| Lough Construction Limited | Construction | 2010 |
| Lough Developments Limited | Real estate | 2000 |
| Lough Developments Lisburn Limited | Real estate | 2014 |
| Lough Services Limited | Administrative & support | 2010 |
| Louie's Properties Limited | Real estate | 2017 |
| Love Culture Ltd | Professional & scientific | 2024 |
| Loveysef Ltd | Wholesale & retail | 2026 |
| Lowe Refrigeration Solutions Limited | Administrative & support | 2005 |
| Lowe Rental Ltd | Administrative & support | 2006 |
| Lowry Grace Consulting Limited | Professional & scientific | 2018 |
| LPD Management Ltd | Professional & scientific | 2009 |
| LR 1 Limited | Administrative & support | 2026 |
| LR 2 Limited | Administrative & support | 2026 |
| Lrob Catering Ltd | Hospitality | 2022 |
| LRR Properties Ltd | Real estate | 2013 |
| LST Haulage Ltd | Transport & logistics | 2018 |
| LTP BIO Ltd | Agriculture & fishing | 2026 |
| LTT Beauty NI Ltd | Other services | 2024 |
| Luce Balloons Ltd | Extraterritorial | 1999 |
| Lucia Rose Properties Limited | Construction | 2024 |
| Luke Carson Consultancy Ltd | Arts & recreation | 2025 |
| Lukris Limited | Construction | 2009 |
| Lumenid Limited | Administrative & support | 2014 |
| Luminacare Diagnostics Ltd | Health & social care | 2025 |
| Lurgan Taxi Co. Limited | Transport & logistics | 2010 |
| Lusk Equestrian Limited | Arts & recreation | 2016 |
| Lustre and Love Jewellery Ltd | Manufacturing | 2023 |
| LUX Leasing Ltd | Wholesale & retail | 2024 |
| LUX Nails & Spa Lisburn Ltd | Other services | 2026 |
| LUX Venetian Plastering Ltd | Construction | 2023 |
| Lvpc Limited | Other services | 2021 |
| Lykke Kitchens Ltd | Construction | 2024 |
| Lyons European Limited | Transport & logistics | 1997 |
| M & M Beauty Services (N.I.) Limited | Other services | 2022 |
| M & S Property Partners Limited | Real estate | 2017 |
| M C Bathrooms Limited | Wholesale & retail | 2023 |
| M C S Building & Joinery Limited | Construction | 2010 |
| M E Crowe Limited | Construction | 2007 |
| M J Hogg Transport Ltd | Transport & logistics | 2014 |
| M Mcroberts Ltd | Professional & scientific | 2010 |
| M O Haodha Ltd | Wholesale & retail | 2022 |
| M Pirooz International Limited | Transport & logistics | 2025 |
| M S Drayne Ltd | Real estate | 2015 |
| M Squared Accommodation Ltd | Real estate | 2022 |
| M Squared Accountancy Ltd | Professional & scientific | 2021 |
| M Squared Artisan Ltd | Hospitality | 2023 |
| M W Johnston & SON Holdings Ltd | Financial services | 2014 |
| M W Johnston & SON Ltd | Mining & quarrying | 2014 |
| M W Johnston & SON Properties Ltd | Real estate | 2014 |
| M&C Auto Services Ltd | Wholesale & retail | 2026 |
| M&D Property Investment Solutions Ltd | Real estate | 2024 |
| M&R Prime Ltd | Real estate | 2024 |
| M.J. Campbell Limited | Manufacturing | 1957 |
| M.J. Moulds Ltd | Transport & logistics | 2018 |
| M.M.G. (N. Ireland) Limited | Real estate | 2012 |
| MAC Inspections Ltd | Construction | 2024 |
| MAC Properties (Crumlin) Limited | Real estate | 2004 |
| MAC Studios Ltd | Information & communication | 2023 |
| Maccorkell Legal & Commercial Limited | Professional & scientific | 2011 |