| Lawless Auto Solutions & Tuning Ltd | Wholesale & retail | 2025 |
| LE Petite Clinique Limited | Other services | 2018 |
| Leafline Garden Care Ltd | Administrative & support | 2025 |
| Lean Supper Club Limited | Hospitality | 2018 |
| Leaning in Ltd | Administrative & support | 2023 |
| Learn to Groom NI Limited | Education | 2025 |
| Learn to Swim With Billy Ltd | Education | 2022 |
| Leen Healthcare Ltd | Administrative & support | 2024 |
| Lega Properties Ltd | Real estate | 2022 |
| Legend Pizza & Kebab House Limited | Hospitality | 2025 |
| Legmore Farms Ltd | Agriculture & fishing | 2009 |
| Lenityni Ltd | Wholesale & retail | 2022 |
| Leobeechill Limited | Administrative & support | 2023 |
| Lettergreen Kennels Ltd | Administrative & support | 2016 |
| Libertas Software Research Limited | Information & communication | 2025 |
| Liberty North Limited | Financial services | 2010 |
| Liberty Water Ltd | Construction | 2023 |
| Lickylix Ltd | Manufacturing | 2022 |
| Lifebrite Ltd | Construction | 2022 |
| Lifewithchristine Ltd | Wholesale & retail | 2026 |
| Lifeworks Developments Limited | Financial services | 2024 |
| Lift-N-Shift (NI) Ltd | Manufacturing | 2014 |
| Liftarch Ltd | Construction | 2026 |
| Liftjuices Ltd | Wholesale & retail | 2025 |
| Lili Forbes Ltd | Wholesale & retail | 2014 |
| Lima Business Solutions Ltd | Financial services | 2025 |
| Lime Park Tack Shop Ltd | Wholesale & retail | 2023 |
| Lindsay & Co Bookkeeping Ltd | Professional & scientific | 2025 |
| Lindsay Mechanical Ltd | Construction | 2024 |
| Linenbundle Holdings Limited | Financial services | 2026 |
| Linenbundle Trading Limited | Wholesale & retail | 2026 |
| LIS Tree Ltd | Agriculture & fishing | 2025 |
| Lisaclare Ltd | Financial services | 2022 |
| Lisavegue Properties Limited | Real estate | 2025 |
| Lisbane Consultants Ltd | Professional & scientific | 2005 |
| Lisburn City Kart Club Ltd | Arts & recreation | 2026 |
| Lisburn Enviro-Care Limited | Mining & quarrying | 2007 |
| Lisburn Road Developments Limited | Real estate | 2004 |
| Lisburnpizzakebab Limited | Hospitality | 2024 |
| Lisnabilla Property Ltd | Real estate | 2017 |
| Lisnavane Ltd | Wholesale & retail | 2017 |
| Lisroan Limited | Extraterritorial | 2010 |
| Lissan Property Developments Limited | Construction | 2006 |
| Litrium Consultancy Limited | Administrative & support | 2022 |
| Little Automation Limited | Construction | 2018 |
| Little Chef LIN Ltd | Hospitality | 2020 |
| Little Engineering Products Limited | Construction | 2018 |
| Little Enterprises (NI) Ltd | Wholesale & retail | 2004 |
| Little Kingdom NI Ltd | Hospitality | 2024 |
| Little Rock Wine Company Limited | Wholesale & retail | 1995 |
| Littmoor Properties Ltd | Real estate | 2025 |
| Live Better Group Limited | Wholesale & retail | 2022 |
| Live by the Word of GOD Ministries International. Ministry to the Less Privileged Persons | Administrative & support | 2018 |
| Live Concert Events Limited | Arts & recreation | 2023 |
| Living Breath Productions Ltd | Information & communication | 2025 |
| Lizara International Limited | Transport & logistics | 2018 |
| LJR Properties Ltd | Real estate | 2003 |
| LK Living Ltd | Wholesale & retail | 2021 |
| Llewellyn Properties Management Limited | Real estate | 2010 |
| Lloyd Acoustics Limited | Construction | 1991 |
| LM Freight Limited | Transport & logistics | 2025 |
| Lobsters ARE Blue Limited | Wholesale & retail | 2023 |
| Lock-A-Block (N.I) Ltd | Manufacturing | 2017 |
| Locum Link Limited | Administrative & support | 2005 |
| Lodgegrove Medicare Limited | Health & social care | 2010 |
| Logos International Limited | Construction | 2024 |
| Loki's Coffee Company Ltd | Wholesale & retail | 2022 |
| Loney Construction Ltd | Construction | 2018 |
| Long Meadow Cider Ltd | Manufacturing | 2014 |
| Longridge (Lurgan) Management Ltd | Households | 2016 |
| Lotus Management Banbridge Limited | Households | 2010 |
| Louanna Ltd | Other services | 2026 |
| Lough Advisory Services Ltd | Wholesale & retail | 2024 |
| Lough Erne Properties Limited | Hospitality | 2021 |
| Lough Grove Management Company Limited | Households | 2018 |
| Lough Holdings Ltd | Financial services | 2018 |
| Lough Neagh Artisan Cheese Company Ltd | Manufacturing | 2021 |
| Lough Neagh Garden Co Ltd - the | Administrative & support | 2005 |
| Lough Neagh Nursing Home Limited | Health & social care | 2022 |
| Lough Shore Enterprises Ltd | Construction | 2022 |
| Loughgall Property Ltd | Households | 2025 |
| Loughran Associates Limited | Construction | 2017 |
| Loughshore Plastering Ltd | Construction | 2025 |
| Loughview Angling Centre Limited | Wholesale & retail | 2019 |
| Loughview Health Ltd | Health & social care | 2023 |
| Loughview Timber Ireland Limited | Manufacturing | 2009 |
| Love for Life | Education | 2002 |
| Love Lurgan CIC | Professional & scientific | 2024 |
| Lowery Consultancy (NI) Ltd | Administrative & support | 2020 |
| LP Transition Limited | Real estate | 1998 |
| LRA Architecture Ltd | Professional & scientific | 2025 |
| LRA Capital and Property Ltd | Construction | 2025 |
| LRC Motorcycle Auctions Ltd | Wholesale & retail | 2024 |
| Lrcmotorcycles Ltd | Wholesale & retail | 2020 |
| Lufor Properties Limited | Real estate | 2025 |
| Lumalo Properties Limited | Hospitality | 2026 |
| Lundy's Fruit Market Limited | Real estate | 1963 |
| Lurban Limited | Construction | 2014 |
| Lurgan Connects Ltd | Wholesale & retail | 2020 |
| Lurgan Forward | Extraterritorial | 1994 |