| DPM Systems | Shropshire |
| DPN Software Ltd | Isle of Man |
| DPSwebsites | Shropshire |
| Dr. Dan Fretwell | |
| DRA | Essex |
| Dradis Framework | |
| DragApp | |
| Dragon Computer Consultancy Ltd | West Midlands |
| Dragon Information Systems | Buckinghamshire |
| Dragon Systems Software Ltd | Worcestershire |
| Dragon2000 Ltd | Northamptonshire |
| Dragonfire Computing | Wrexham County Borough |
| Dragonfly AI | |
| Dragonfly Technology | |
| Draig Therapeutics | |
| Draka UK Ltd | Hampshire |
| Draw & Code | |
| Draw Pictures Ltd | |
| draw.io | |
| Draycir | Leicestershire |
| DRD Communications Ltd | Greater London |
| DrDoctor | |
| Dream Harvest | |
| Dream Reality Interactive Ltd | |
| Dreams Technologies | |
| Dreamscape Solutions | |
| Dreamscape-Web Ltd | North Yorkshire |
| Dreamsight Internet Ltd | Gloucestershire |
| Drest | Greater London |
| Drewl | |
| Drift Digital | |
| Driftrock | |
| DRiiVE | |
| Drill Surgeries Ltd | |
| Drishti Discoveries | |
| dRISK Ltd | |
| Drive Creative Studio Ltd | |
| Driven By Digital | |
| Driven Corp Ltd | |
| Driven Design | |
| Driver Intelligence Ltd | |
| DriverNet | |
| Dronamics | |
| Drone Defence | |
| Dropit Shopping | |
| Droplet Computing | |
| DRUM Studios Ltd | |
| Drumbeaters Ltd | |
| Drumlin Business Services | Newry, Mourne and Down |
| Drupology | |