| Dragons Tail Events Limited | Arts & recreation | 2025 |
| Drain Heroes Limited | Water & waste | 2018 |
| Drake Memorial Park Holdings Limited | Financial services | 1993 |
| Drakes Drive 1963 Limited | Extraterritorial | 2014 |
| Drarete Ltd | Professional & scientific | 2012 |
| Drcee Solutions Limited | Professional & scientific | 2018 |
| Dream Team Movers Limited | Transport & logistics | 2016 |
| Drew Knight Hospitality Ltd | Hospitality | 2022 |
| Drew Wharf NO. 2 Management Limited | Households | 2017 |
| DRH Supply Chain Solutions Ltd | Professional & scientific | 2018 |
| Drink Command UK Ltd | Manufacturing | 2021 |
| Drink Evolution Ltd | Hospitality | 2025 |
| Drink Skip Limited | Manufacturing | 2023 |
| Drinksmiths Ltd | Administrative & support | 2019 |
| Drive Thru MOT Limited | Wholesale & retail | 2008 |
| Drivesp Ltd | Transport & logistics | 2025 |
| Driving Matters Ltd | Education | 2020 |
| Drmtconsulting Limited | Information & communication | 2025 |
| Dronework Worldwide Limited | Information & communication | 2022 |
| Drop IT Already Ltd | Professional & scientific | 2025 |
| Droplets Studio Ltd | Information & communication | 2026 |
| Drotsky Ltd | Arts & recreation | 2023 |
| DRS Media Limited | Administrative & support | 2020 |
| Druce & Partners Limited | Real estate | 2003 |
| Druce Cars Ltd | Wholesale & retail | 2020 |
| Drylock Technologies Limited | Administrative & support | 2016 |
| Dryrz Ltd | Wholesale & retail | 2025 |
| Drytex UK Limited | Construction | 1995 |
| Drywall Consultants Ltd | Professional & scientific | 2024 |
| DSK Learning Ltd | Professional & scientific | 2021 |
| DT Rescue Ltd | Transport & logistics | 2025 |
| DU Preez Active Holdings Ltd | Arts & recreation | 2025 |
| Dubl Clothing Limited | Wholesale & retail | 2023 |
| Duepro Limited | Construction | 2012 |
| Duffy Archive Limited | Arts & recreation | 2008 |
| Duffy Media Ltd | Manufacturing | 2018 |
| Dull Problems Solved Quickly Ltd | Professional & scientific | 2018 |
| Dumbarton Edwards Contracts Limited | Construction | 2023 |
| Dumbarton Edwards Property Limited | Construction | 2026 |
| Dunn GI Limited | Health & social care | 2012 |
| Dunrite Preservation Company Limited | Construction | 2002 |
| Dunsar Media Company Limited | Information & communication | 2009 |
| Dunstable Residents Association Limited | Real estate | 1972 |
| Duraseal Print Finishers Limited | Manufacturing | 2009 |
| Duraware Ltd | Professional & scientific | 1995 |
| Durlston Consultancy Services Limited | Professional & scientific | 2017 |
| Durum Opus Ltd | Professional & scientific | 2026 |
| Dusk Immigration Ltd | Professional & scientific | 2024 |
| Dvoika Limited | Wholesale & retail | 2016 |
| Dvorak Midco 1 Limited | Professional & scientific | 2020 |
| Dvorak Midco 2 Limited | Professional & scientific | 2020 |
| Dvorak Topco Limited | Professional & scientific | 2020 |
| DVW Enterprise Ltd | Administrative & support | 2023 |
| DW Comms Limited | Information & communication | 2012 |
| DW Information Systems Ltd. | Information & communication | 2015 |
| Dwayne Edwards Limited | Construction | 2002 |
| Dwrs Services Ltd | Agriculture & fishing | 2025 |
| DWS Holdings Ltd | Financial services | 2021 |
| DWX10 Ltd | Professional & scientific | 2024 |
| Dy.Da. Ltd | Real estate | 2021 |
| DYD Services Ltd | Transport & logistics | 2025 |
| Dyer’S Plasterworks Ltd | Construction | 2021 |
| Dylans ST Albans Ltd | Hospitality | 2014 |
| Dynamic Draughting Services Limited | Professional & scientific | 2014 |
| Dynamic Heating & Air Conditioning Ltd | Construction | 2019 |
| Dynamic Publishing Ltd | Information & communication | 2024 |
| Dynastay Ltd | Real estate | 2022 |
| Dyvik & Kahlen Ltd | Professional & scientific | 2010 |
| DZX Ltd | Financial services | 2020 |
| Décor Fabrications Limited | Manufacturing | 2023 |
| E & C Builders Limited | Construction | 2008 |
| E & S Installations Ltd | Construction | 2019 |
| E F Consulting Limited | Professional & scientific | 2006 |
| E Logan Consultancy Ltd | Professional & scientific | 2023 |
| E. P. Solutions (UK) Limited | | 2005 |
| E.B.Construction Services Ltd | Construction | 2017 |
| E.D. Elson Limited | Wholesale & retail | 1968 |
| E2 Consulting Limited | Education | 2021 |
| E2EX Limited | Professional & scientific | 2024 |
| E7R Ltd | Information & communication | 2020 |
| EA Catering Services Ltd | Hospitality | 2020 |
| Eagle BJJ Ltd | Education | 2026 |
| Eagle Design & Build Ltd | Construction | 2013 |
| Eagle Maintenance and Cleaning Services Ltd | Construction | 2018 |
| Earendil Limited | Financial services | 2022 |
| Earley Property Co. Limited | Construction | 1949 |
| Earlham Risk and Management Services Ltd | Professional & scientific | 2024 |
| Earlsfield Capital - Lido Learning LLP | | 2020 |
| Earth Potential LLP | | 2008 |
| Earthwalker Limited | Information & communication | 2018 |
| Earthworks ST Albans | Health & social care | 1997 |
| East Twenty Limited | Real estate | 2021 |
| Eastbury Court Management Company (ST. Albans) Limited | Households | 1998 |
| Eastern Logistics Inc Ltd | Wholesale & retail | 2025 |
| Eastern West Ltd | Other services | 2015 |
| Easthall Farms Trading Ltd | Agriculture & fishing | 2023 |
| Easton IT Training Limited | Information & communication | 2008 |
| Easy Lift Ltd | Administrative & support | 2010 |
| EAT Honest Limited | Hospitality | 2013 |
| EAT OUT Limited | Wholesale & retail | 2024 |