| Lake IT Consultancy Belfast Limited | Information & communication | 2024 |
| Lake View Services Ltd | Wholesale & retail | 2014 |
| Lakeland Health Village Limited - the | Real estate | 1999 |
| Lakeland Living Ltd | Real estate | 2023 |
| Lakeland Properties (NI) Limited | Construction | 2009 |
| Lakeland Tyres Belfast Limited | Wholesale & retail | 2014 |
| Lakeside Compliance Services Ltd | Administrative & support | 2020 |
| Lakeview Property Management Company (NO.2) Limited | Extraterritorial | 2009 |
| Lakeview Property Management Limited | Households | 2008 |
| Lakshya Gold Limited | Hospitality | 2021 |
| Lalamar Holdings Limited | Financial services | 2025 |
| LAM Architects Ltd | Professional & scientific | 2018 |
| LAM Properties (N.I.) Ltd | Real estate | 2025 |
| LAM Recoveries Limited | Extraterritorial | 2020 |
| Lamb Films Ltd | Information & communication | 2008 |
| Lambdan Industrial Limited | Wholesale & retail | 2025 |
| Lambert Smith Hampton Group Limited | | 1992 |
| Lambird Limited | Financial services | 2018 |
| Lambs Landscapes Ltd | Administrative & support | 2024 |
| Lameno Limited | Hospitality | 2018 |
| Lamicall Innovations Malta Limited | Wholesale & retail | 2026 |
| Laminin 316 Ltd | Professional & scientific | 2016 |
| Lampert House Limited | Extraterritorial | 1987 |
| Lamsam 2018 Ltd | Transport & logistics | 2018 |
| LAN AR Aghaidh Ltd | Real estate | 2025 |
| LAN Chun HUA Limited | Wholesale & retail | 2025 |
| Lana Kearney Social Ltd | Professional & scientific | 2025 |
| Lanamore Properties Ltd | Real estate | 2025 |
| Lanark Business Park Management Company Ltd | Other services | 2025 |
| Lanark Homes Limited | Professional & scientific | 1995 |
| Lanark Plumbing Services Ltd | Construction | 2018 |
| Lanark Solutions (Belfast) Ltd | Wholesale & retail | 2022 |
| Lanark Supplies &Services Ltd | Other services | 2022 |
| Lancaster Park (Cairnshill) Management Company Limited | Households | 2021 |
| Lancedean Limited | Real estate | 1950 |
| Lancefield Radiology Limited | Health & social care | 2023 |
| Landar Group Ltd | Construction | 2019 |
| Landbrook Management Limited | Extraterritorial | 1988 |
| Landers Properties Limited | Extraterritorial | 1987 |
| Landfall Consulting Limited | Professional & scientific | 2023 |
| Landley Developments Ltd | Construction | 2011 |
| Landlord and Tenant Protection Limited | Information & communication | 2022 |
| Landlord's Association for Northern Ireland Limited | Other services | 2016 |
| Landmark Housing & Developments Limited | Administrative & support | 1998 |
| Landmore Properties Limited | Real estate | 2007 |
| Landour Services Ltd | Professional & scientific | 2017 |
| Landscape Enterprise Holding Limited | Financial services | 2023 |
| Landscape Enterprise Limited | Wholesale & retail | 2010 |
| Landstyle Worldwide L.P. | | 2018 |
| Landwick Group LP | | 2019 |
| Langham Estate Planning & Rentals Ltd | Administrative & support | 2013 |
| Langhua Ltd | Wholesale & retail | 2024 |
| Langley 2014 Limited Partnership | | 2014 |
| Langley Hall Services (Number 2) Limited | Extraterritorial | 2001 |
| Langley Hall Services (Number 3) Limited | Households | 2002 |
| Langley Hall Services Limited | Extraterritorial | 1997 |
| Langtree Limited | Construction | 2003 |
| Langtry Court Management Company Limited | Extraterritorial | 1999 |
| Lanita Properties Ltd | Construction | 2014 |
| Lannister Farm Limited | Agriculture & fishing | 2019 |
| Lansdowne Court Management Ltd | Households | 2011 |
| Lansdowne Road Property Management Company Limited | Extraterritorial | 2000 |
| Lanstar Northern Ireland Limited | Extraterritorial | 1991 |
| Lanum Williams Limited | Professional & scientific | 2020 |
| Lanxiongda Technology Company Limited | Wholesale & retail | 2025 |
| Lanyon Capital Ltd | Professional & scientific | 2012 |
| Lanyon Communications Limited | Professional & scientific | 2006 |
| Lanyon Finance Limited | Extraterritorial | 2016 |
| Lanyon Financial Planning Limited | Financial services | 2001 |
| Lanyon Homes NI Limited | Real estate | 2015 |
| Lanyon Investments Limited | | 2005 |
| Lanyon Place Limited | Real estate | 2008 |
| Lanyon Place Management Company Limited | Real estate | 1995 |
| Lanyon Property Consultants Limited | Construction | 2004 |
| Lanyon Property Management Company Limited | Extraterritorial | 2004 |
| Lanyon Quay Secretarial Services Ltd | Administrative & support | 2005 |
| Lanza Autos Ltd | Extraterritorial | 2023 |
| LAO Consultants Ltd | Professional & scientific | 2000 |
| Lapd Developments Limited | Professional & scientific | 2007 |
| Laposa Ltd | Information & communication | 2009 |
| Lappin Construction (NI) Limited | Construction | 2011 |
| Laptop and PC Warehouse Ltd | Wholesale & retail | 2020 |
| Lara Developments Limited | Construction | 2002 |
| Larch Propertyco Holdco Limited | Arts & recreation | 2020 |
| Lareva Consultancy Limited | Health & social care | 2009 |
| Largey Consulting Limited | Professional & scientific | 2017 |
| Largeys Ltd | Hospitality | 2022 |
| Largoline United L.P. | | 2018 |
| Largomax Universal L.P. | | 2018 |
| Lark Sheep Limited | Manufacturing | 2024 |
| Larkfield Construction Ltd | Construction | 2025 |
| Larkfield Developments Limited | Construction | 1986 |
| Larkfield Properties Limited | Real estate | 2014 |
| Larkhill Properties Limited | Construction | 2007 |
| Larkmake Limited | Real estate | 2020 |
| Larkspur Management Company Limited | Households | 2000 |
| Larkstone Capital Limited | Real estate | 2022 |
| Larkville Limited | Real estate | 2016 |
| Larmour Estates Limited | Real estate | 2011 |
| Larmour Investigations Ltd | Administrative & support | 2005 |