| HeightOn | |
| Helio Display Materials | |
| Helio Fintech Ltd | |
| Helion Technology Licensing Ltd | Cambridgeshire |
| Helios Internet Systems | |
| Helipaddy Ltd | |
| Hellenic Systems Ltd | Essex |
| HellermannTyton Data Ltd | Northamptonshire |
| HellermannTyton Ltd | Greater Manchester |
| Hello Telecom (UK) plc | Nottinghamshire |
| Hello Wired | |
| HelloDone Ltd | |
| Helm Training | |
| Help Desk World | Berkshire |
| HelpAI | |
| Helpful Ltd | |
| Helyx Secure Information Systems Ltd | Gloucestershire |
| Hemel Hempstead RISC User Group | Hertfordshire |
| Hemplan Design Ltd | |
| Hempsell Astronautics Ltd | |
| Hempsons, LLP | |
| Hemsley Fraser Group Ltd | |
| Hence Technologies Ltd | |
| Henley Business School | |
| HepcoAutomation | |
| Her Majesty's Government Communications Centre | Buckinghamshire |
| Herald Information Systems | Surrey |
| Herbert Group | Suffolk |
| Herdl Ltd | Leicestershire |
| Here East | |
| Hereford Software Solutions | Herefordshire |
| Herefordshire Linux User Group | Herefordshire |
| Herga Technology Ltd | Suffolk |
| Herian IT Support | West Sussex |
| Heriot-Watt University - Computer Science | Edinburgh |
| Heriot-Watt University - Electrical, Electronic & Computer Engineering | Edinburgh |
| Heriot-Watt University - Mathematics | Edinburgh |
| HERmesa | |
| Hero Futures Energies | |
| Herodsfoot Webworks | Cornwall |
| Heronic | |
| Herriot-Watt University | Edinburgh |
| Herron + Co. | South Yorkshire |
| Herron Design Ltd | |
| Herschel Systems Ltd | Buckinghamshire |
| Hertford Media | |
| Hertility Health | |
| Herts for Learning | |
| Hertscom IT Ltd | Hertfordshire |
| Hertsmedia | Hertfordshire |