| Huboo Technologies Ltd | Bristol |
| HubStar | |
| HUBX Capital | |
| Huckletree | |
| Huddled Media Agency Ltd | |
| Hudson Outsourcing | |
| Hue&Machine | |
| Hugo Technology Ltd | |
| Hull York Medical School | |
| Hullabalook | |
| Huma | Greater London |
| Humaans | |
| HUMAIN Ltd | |
| Human Crafted Technology Ltd | Dorset |
| Human Made Ltd | |
| HumanForest Ltd | |
| Humanise.AI | Greater London |
| Humanising Autonomy | |
| Humanising Autonomy Ltd | Greater London |
| Humanotics Ltd | |
| Humley | |
| Hummingbird Ventures | Greater London |
| Hummingbirg Technologies Ltd | |
| Humn | Greater London |
| Hunted Cow Studios Ltd | Moray Council |
| Hunter Bevan Ltd | |
| Hurley Design | West Sussex |
| Hurree, Inc. | |
| Hurst Group | Essex |
| Hush Digital | County Durham |
| Husky Intelligence | |
| Hussey Coding Ltd | West Midlands |
| Hutch House Digital Media | |
| Hutchison 3G UK Ltd | Berkshire |
| Huxley Digital | |
| Huxo | |
| Huzzah! Digital | |
| hVIVO Services Ltd | |
| HW Technology Ltd | Lancashire |
| HW Ventures Ltd | |
| Hybiscus | |
| Hybrid Touch Games Ltd | |
| Hydra Creative Ltd | South Yorkshire |
| Hydra Management | Hampshire |
| Hydrasun | |
| Hydro | |
| Hydro Wind Energy | |
| Hydrogel Healthcare Ltd | |
| HydroSurv Unmanned Survey (UK) Ltd | Devon |
| Hyfinity Ltd | West Midlands |