| Raspberry Pi | |
| Raspberry Pi Foundation | Cambridgeshire |
| Raspberry Software Ltd | |
| RateGain | Greater London |
| Ratio Software Engineering | Greater London |
| Ratio7 | Hertfordshire |
| RatwareUK Ltd | Lancashire |
| Ravelin Technology Ltd | |
| Raven Code Ltd | |
| Raven Computers Ltd | West Yorkshire |
| Ravenbridge Ltd | West Sussex |
| Ravenbrook Ltd | Cambridgeshire |
| Ravensbourne University London | |
| Ravensmith Ltd | |
| Ravenswood Media Ltd | |
| Ravio | Greater London |
| Raw Charging | |
| RAW Technical Services Ltd | South Yorkshire |
| Rawcode Computer Consultancy Ltd | |
| Rawlings Atlantic | |
| Rawnet Digital Agency | |
| Rawstream | |
| Rawww Ltd | West Midlands |
| Ray Solutions | |
| Raycom Ltd | Worcestershire |
| Rayipudi Software Solutions | |
| Rayleigh Computer Shop | Essex |
| Raylo Group Ltd | |
| Rayner Group | |
| Raznameh Group | |
| Razor Ltd | |
| Razorblue | North Yorkshire |
| RazorSecure Ltd | |
| RB Web Design | Suffolk |
| RBSEO | |
| RCS UK | Surrey |
| RCW HR Solutions | |
| RD Internet | |
| RD&M Web Designers | |
| RDC Aviation Ltd | |
| RDDS Avionics Ltd | Kent |
| Re-Tek UK Ltd | South Lanarkshire |
| Re-Vana Therapeutics | |
| Re-Work | |
| RE:Internet Systems Ltd | Derbyshire |
| Reach Digital | |
| Reach plc | |
| Reach Separations | |
| Reach Studios Ltd | |
| React Advanced | |