| Kimmie Nails and Spa Ltd | Other services | 2026 |
| Kincom Limited | Professional & scientific | 2025 |
| Kingdom Harvest Church Belfast | Other services | 2016 |
| Kingdom Keys Property Group Ltd | Real estate | 2026 |
| Kingfu Bangor Ltd | Hospitality | 2024 |
| Kingsbridge Caravan Park Limited | Hospitality | 2021 |
| Kingsfield Enterprises Limited | Health & social care | 2008 |
| Kinnear Consulting Ltd | Professional & scientific | 2015 |
| KIRK123 Ltd | Real estate | 2023 |
| Kirkpatrick Property Management Limited | Real estate | 2017 |
| Kirkside Estates Limited | Real estate | 1996 |
| KJK Groundworks & Plant Sales Limited | Construction | 2018 |
| Klerps Ltd | Real estate | 2024 |
| Klever Kreations Ltd | Manufacturing | 2025 |
| Kmac Workplace Solutions Ltd | Wholesale & retail | 2022 |
| KMF International Education Consultants Limited | Education | 2025 |
| Knead and Prove Ltd | Manufacturing | 2019 |
| Knock Management Limited | Extraterritorial | 1987 |
| Knock River Property Management Ltd | Extraterritorial | 2015 |
| Knockan Lodge (Ballymoney) Ltd | Real estate | 2019 |
| Knockmarloch Manor Limited | Professional & scientific | 2002 |
| KP Clonmor Limited | Health & social care | 2014 |
| KPL Commercial Limited | Real estate | 2020 |
| Krackenservices Ltd | Information & communication | 2023 |
| Krag Expeditions Ltd | Arts & recreation | 2026 |
| Kula Consulting & Training Ltd | Health & social care | 2026 |
| Kwart Ltd | Arts & recreation | 2024 |
| Kynra Group Ltd | Wholesale & retail | 2025 |
| L Haworth Landscaping & Construction Ltd | Construction | 2024 |
| L-Ectrical LW Limited | Construction | 2022 |
| L. & N. James Investment Properties (Cheadle) Limited | Real estate | 1960 |
| L.A.R. (North Down) Ltd | Administrative & support | 2006 |
| Labriola Consultancy Limited | Education | 2025 |
| Ladybirds Children's Services | Education | 2020 |
| Lagan Lutherie School Limited | Education | 2017 |
| Laird Contracts Limited | Construction | 1981 |
| Landlord Direct Supplies Ltd | Wholesale & retail | 2024 |
| Lane & Lane (N.I.) Ltd | Wholesale & retail | 2018 |
| Lane 44 Ltd | Wholesale & retail | 2019 |
| Lane Inn Limited | Hospitality | 2016 |
| Langdon Apartments Limited | Extraterritorial | 1984 |
| Larkin Tree Care Ltd | Administrative & support | 2025 |
| Laser Clinic (North Wales) Ltd | Other services | 2011 |
| Lastra Farm Hotel Limited | Hospitality | 2001 |
| Laundry Room (Bangor) Limited | Wholesale & retail | 2018 |
| Laura EVE Dougherty Ltd | Professional & scientific | 2020 |
| Laura Flinn Dent Ltd | Health & social care | 2026 |
| Lavish the Mart Limited | Wholesale & retail | 2025 |
| Law Quinn Solicitors Ltd | Professional & scientific | 2021 |
| Lawford Analytics Limited | Information & communication | 2016 |
| Lawford Technologies Limited | Information & communication | 2023 |
| Lawford Ventures Limited | Financial services | 2023 |
| Lawton Facilities Ltd. | Construction | 2021 |
| LBH (N.I.) Limited | Real estate | 2019 |
| LBP Consumer Product Limited | Manufacturing | 2023 |
| LD Property and Maintenance Ltd | Real estate | 2023 |
| LDS Promotions NW Ltd | Information & communication | 2026 |
| Lead Accounting Limited | Professional & scientific | 2023 |
| Lead Partners CA Ltd | Households | 2024 |
| Leanne's Hair & Beauty Limited | Other services | 2020 |
| Learnforward Leadership Academy CYF | Information & communication | 2025 |
| Learning Links International C.I.C. | Education | 2011 |
| LEE & Jordy Valeting and Detailing Ltd | Administrative & support | 2022 |
| Legal Searches (NI) Limited | Professional & scientific | 2016 |
| Lennox Agencies Ltd | Wholesale & retail | 2008 |
| Lensflair Ltd | Professional & scientific | 2019 |
| Lepalmar Group Ltd | Real estate | 2026 |
| Let's Build WP Ltd | Professional & scientific | 2015 |
| Lewington & Templer Ltd | Construction | 2007 |
| Lgfcv Ltd | Administrative & support | 2023 |
| Liam Burns Limited | Other services | 2020 |
| Liangcaizha Ltd | Wholesale & retail | 2024 |
| Lifestyle Real Estate (NI) Limited | Real estate | 1998 |
| Light Future Ltd | Professional & scientific | 2019 |
| Light Image Design Limited | Professional & scientific | 2015 |
| Lightfoot Zero Waste Market Ltd | Wholesale & retail | 2022 |
| Lighthouse Commerce Ltd | Wholesale & retail | 2025 |
| Lightyear Plumbing & Heating Limited | Other services | 2006 |
| Lilburn Industrial Property Limited | Real estate | 2025 |
| Lily Wood Lane Management Company Limited | Households | 2017 |
| Linensy Ltd | Wholesale & retail | 2025 |
| Lineybrook Lane Management Limited | Households | 2004 |
| Lingar Holdings (Chester) Limited | Financial services | 2013 |
| Links Management Company Limited - the | Households | 1998 |
| Linzi Grace Parties and Workshops Limited | Wholesale & retail | 2018 |
| Lips & Lashes Palour Limited | Other services | 2019 |
| Liquids Research Limited | Manufacturing | 1994 |
| Lisa Capper Limited | Health & social care | 2022 |
| Lisdarg Limited | Real estate | 2001 |
| Lisnaree Limited | Construction | 2014 |
| Listullycurran Properties Ltd | Real estate | 2005 |
| Little Bears Private Day Nursery Ltd | Education | 2012 |
| Little Citizens Boutique Ltd. | Wholesale & retail | 2012 |
| Little Deer's Day Nursery Limited | Health & social care | 2025 |
| Little Kingdom Kids (Carrowdore) Ltd | Health & social care | 2020 |
| Little Seedlings (NI) Ltd | Health & social care | 2014 |
| Little Wren Property Ltd | Real estate | 2021 |
| Live Love Yoga Ltd | Education | 2025 |
| Liverpool Music Village Ltd | Mining & quarrying | 2006 |
| Liverpool Road Chester Limited | Construction | 2017 |