| Receptional | Bedfordshire |
| Recipero Ltd | Gloucestershire |
| Reckitt Benckiser Group plc | |
| Reckless | Cheshire |
| Recktangle | |
| Recruit Genie (Europe) Ltd | |
| Recruit Studio Ltd | West Sussex |
| Recruit121 | |
| RecruiTeams Group Ltd | |
| RecruiterWEB | Cambridgeshire |
| Recruitive Limited | Staffordshire |
| Recruitment Entrepreneur | |
| Rectangle Red Ltd | Buckinghamshire |
| Rectangular Software Ltd | |
| RecycledIT | Cambridgeshire |
| Red 2 Design Ltd | |
| Red Ant Solutions | |
| Red Badger Consulting Ltd | |
| Red Box Recorders Ltd | Nottinghamshire |
| Red Box Web Design Ltd | Staffordshire |
| Red Bullet | |
| Red C Mobile Ltd | Greater London |
| Red Cow Media | Greater Manchester |
| Red Dot Now | |
| Red Dragon Webmaster | |
| Red Evolution Ltd | Aberdeen |
| Red Eye International Ltd | Cheshire |
| Red Feather Solutions Ltd | |
| Red Frog Studio | |
| RED Global | |
| Red Goat Cyber Security | |
| Red Graphic Cambridge Ltd | |
| Red Hot Penny | Berkshire |
| Red Kestrel Consulting Ltd | Staffordshire |
| Red Ninja Ltd | |
| Red Paint Multimedia Ltd | |
| RED RABBIT Software Ltd | West Sussex |
| Red Rhino Web Design Northern Ireland | Armagh City, Banbridge and Craigavon |
| Red River Solutions | |
| Red Robot Ltd | |
| Red Rocket Digital | |
| Red Rocket Web Design Ltd | Suffolk |
| Red Rose Internet Ltd | County Durham |
| RED Semiconductor International Ltd | |
| Red SIft | |
| Red Sky | |
| Red Software Development | |
| Red Squirrel Digital Ltd | |
| Red-Fern Media Solutions Ltd | |
| Red61 | Edinburgh |