| Disking International Ltd | |
| DiskInternals UK | |
| Disklabs Ltd | Staffordshire |
| Diskovery Associates Ltd | |
| Dispense Digital | |
| Disperse | |
| Displaydata Ltd | Berkshire |
| DisplayNote Technologies Ltd | |
| Disrupt Learning | |
| Disruption Works Ltd | |
| Distance Learning Centre | |
| Distec Ltd | Greater Manchester |
| Distill Ventures (London) Ltd | |
| Distinct Cloud Labs | |
| Distinct Strategies | |
| Distinction Ltd | |
| Distinctive Systems Ltd | North Yorkshire |
| Distinctly | Hertfordshire |
| Distortion Ltd | Leicestershire |
| Distributed, Inc. | |
| DISUK | Northamptonshire |
| Ditronic Software | Buckinghamshire |
| Dittofi Ltd | |
| Diurnal Ltd | |
| Diverse Interactive | |
| Diversity VC | Greater London |
| Divide and Conquer | |
| DivideBuy | |
| Divido | Greater London |
| Divr Labs | |
| DIY Accounting Ltd | Tyne and Wear |
| DJA Online Services Ltd | |
| DjangoCon EU 2023 | |
| Djinn Technologies Ltd | |
| DJS Antibodies | |
| DJS Research | |
| DKC Software | |
| DKT Group | Cornwall |
| Dlphin Maritime Software Ltd | Lancashire |
| DLR Consultants | |
| DLR Media | |
| DLX Networks | East Sussex |
| DM Optics Ltd | Somerset |
| DM Web Solutions | |
| DMB Computers | Nottinghamshire |
| DMB Design | South Yorkshire |
| DMC Technology (Scotland) Ltd | Aberdeen |
| DMC Web Services | Edinburgh |
| DMJ Computer Services | Wiltshire |
| DMTesseracT Ltd | |