| D Sweeney Motors Limited | Wholesale & retail | 2018 |
| D&J Music Group Ltd | Information & communication | 2024 |
| D2 Enterprises Ltd | Real estate | 2004 |
| DA Belmore Street Ltd | Other services | 2019 |
| Daisy Hill Ltd | Professional & scientific | 2020 |
| Damandus Limited | Extraterritorial | 2013 |
| Damback Farm Ltd | Agriculture & fishing | 2023 |
| Damian Kelly Electrical Ltd | Construction | 2024 |
| Damian Martin Electrical Limited | Construction | 2016 |
| Damien Aiken Electrical Ltd | Construction | 2018 |
| Damiraco Limited | Hospitality | 2012 |
| Dampmaster Ltd | Professional & scientific | 2023 |
| Dan's Campers Ltd | Wholesale & retail | 2025 |
| Daniel Anthony's Hair Ltd | Other services | 2019 |
| Danrose Limited | Construction | 2015 |
| Daphne Mahon Limited | Real estate | 2005 |
| Darby House Kitchens & Bedrooms Ltd | Manufacturing | 2024 |
| Darcon Limited | Construction | 2016 |
| Darhide Investments Limited | Financial services | 2021 |
| Dark Luxury Tanning Ltd | Other services | 2023 |
| Darren Sweeney Electrical NI Ltd | Construction | 2018 |
| David & Shane Ltd | Construction | 2005 |
| David IAN Campbell Ltd | Real estate | 2010 |
| David Mahon Properties Limited | Real estate | 1993 |
| David Robert Mahon Ltd | Wholesale & retail | 2002 |
| DBS Engineering Solutions Ltd | Professional & scientific | 2025 |
| Ddmcc Ltd | Real estate | 2016 |
| Deane Plant Limited | Construction | 2012 |
| Deane Public Works Limited | Construction | 1986 |
| Deckchair Travel Limited | Administrative & support | 2025 |
| DECOR8 Contracts Ltd | Construction | 2016 |
| Deerpark Collections Limited | Water & waste | 2005 |
| Deirdre Burns Aesthetics & Skin Clinic Ltd | Other services | 2025 |
| Denzil Jones Transport Ltd | Transport & logistics | 2025 |
| Derconn Developments Limited | Real estate | 2015 |
| Dernasell Transport Ltd | Transport & logistics | 2024 |
| Derrallen Service Station Ltd | Wholesale & retail | 2022 |
| Derrin Ltd | Financial services | 2026 |
| Derryad Holiday Development Company Limited | Extraterritorial | 1990 |
| Derrychara Properties Limited | Construction | 2006 |
| Derrygiff Properties Limited | Real estate | 2020 |
| Derrygonnelly Health and Wellbeing Ltd | Arts & recreation | 2022 |
| Derrygore Enterprises Ltd | Wholesale & retail | 2021 |
| Derryheanlish Farms Ltd | Agriculture & fishing | 2023 |
| Derrylin & Ballyconnell Dental Implant Centre Ltd | Health & social care | 2010 |
| Derrylin Enterprises Limited | Administrative & support | 1998 |
| Derrylin Pharmacy Ltd | Health & social care | 2012 |
| Deso Brat Ltd | Hospitality | 2019 |
| Devenish Bar Ltd | Hospitality | 2011 |
| Devenish Partnership Forum | Health & social care | 2002 |
| Devenish PUB (Enniskillen) Ltd | Hospitality | 2018 |
| Devine and Associates Drummee Ltd | Energy | 2012 |
| Devine and Associates Ltd | Construction | 2007 |
| Devine Holdco Ltd | Financial services | 2025 |
| DF Financial Limited | Financial services | 2026 |
| DFE International Ltd | Wholesale & retail | 2024 |
| DG Marine Worx Limited | Wholesale & retail | 2021 |
| Dgca Limited | Professional & scientific | 2016 |
| Diamond Cabs and Coach Hire Limited | Transport & logistics | 2011 |
| Diamond Landscapes Ltd | Administrative & support | 2026 |
| Digi Repairs (UK & Ireland) Limited | Manufacturing | 2004 |
| Direct Haulage Ltd | Transport & logistics | 2013 |
| Diver Offshore Limited | Other services | 2018 |
| Dixon Marine Ltd | Other services | 2012 |
| DIY Regenerate Paints Ltd | Wholesale & retail | 2023 |
| DJB Limited | Extraterritorial | 2026 |
| DLG Water Limited | Water & waste | 2016 |
| DLJ Water Limited | Water & waste | 2020 |
| DM Power Control Ltd | Construction | 2026 |
| Dmac Building & Construction Ltd | Construction | 2017 |
| DMC Mechanical Ltd | Manufacturing | 2020 |
| DMC T/A Soil Science NI Ltd | Wholesale & retail | 2025 |
| DMD (UK & Ireland) Limited | Professional & scientific | 2018 |
| DMG Projects Limited | Construction | 2025 |
| DMP Storage Limited | Transport & logistics | 2019 |
| Dollakis Co Ltd | Hospitality | 2008 |
| Dollakis in the Park Limited | Hospitality | 2017 |
| Dolpher Contracts Ltd | Construction | 2025 |
| Domer Solutions Limited | Administrative & support | 2019 |
| Donal Corrigan Joinery & Construction Limited | Construction | 2018 |
| Donard Investments Limited | Real estate | 2004 |
| Donegan Delivery Limited | Transport & logistics | 2013 |
| Donellagh Construction Services Limited | Construction | 2020 |
| Doon Wind Limited | Energy | 2013 |
| Doonan Farms Ltd | Agriculture & fishing | 2014 |
| Dowlers Ltd | Wholesale & retail | 2021 |
| DR Dyer's Dairy Goat Farm Limited | Agriculture & fishing | 2018 |
| DR Electrical (NI) Limited | Construction | 2013 |
| Dr.Mary Catherine Ltd | Health & social care | 2021 |
| Dromore Vivo Ltd | Wholesale & retail | 2025 |
| Drumadraghy Motors Limited | Wholesale & retail | 2002 |
| Drumcanon Engineering Ltd | Administrative & support | 2017 |
| Drumclay Court Management Co Limited | Real estate | 2017 |
| Drumder Eggs Ltd | Wholesale & retail | 2024 |
| Drumderg Electrical Services Ltd | Construction | 2021 |
| Drumdoney Properties Limited | Real estate | 2017 |
| Drumgallan Crescent Management Company Ltd | Households | 2021 |
| Drumgarra Construction Limited | Construction | 2020 |
| Drumgarrow Management Company Ltd | Administrative & support | 2007 |
| Drumgarrow Village Management Company Ltd | Real estate | 2020 |