| Radley Yeldar | Greater London |
| RAE Computing Ltd | West Yorkshire |
| Rafaquat Ali | |
| Raft | |
| Raid Host | |
| Railsbank Technology Ltd | Greater London |
| Railsite Telecom | |
| Rainbird | Norfolk |
| Rainbirdsoft Ltd | |
| Raindrop Digital Ltd | |
| Rainmaker Solutions | |
| Rainmaking Innovation Ltd | |
| Rainy City Agency Ltd | |
| Rak Design (UK) Ltd | Northamptonshire |
| RAK Printed Circuit Boards Ltd | Essex |
| Rakata Technology Ltd | |
| RAL Space | |
| Ram Infosystems Ltd | |
| RAM Tracking | |
| Ramarketing | |
| Ramp | Greater London |
| Ramp Swaps Ltd | |
| Rampart Capital, LLP | |
| Random International | |
| Random Surfer Ltd | |
| Randox Biosciences Ltd | |
| Randox Laboratories Ltd | |
| Rank No.1 | |
| RankedRight Ltd | |
| Ranking Algorithms | Merseyside |
| RankSnack UK | |
| Rantmedia | Cardiff |
| Ranyart Systems Ltd | |
| Raphael Design Ltd | Staffordshire |
| Rapid Agency | |
| Rapid Computers Ltd | Greater London |
| Rapid Electronics Ltd | Essex |
| Rapid SEO London | Greater London |
| Rapid Vision Systems | |
| Rapid Web Ltd | Staffordshire |
| RapidSpike | |
| RapidSwitch | Berkshire |
| Rapita Systems Ltd | North Yorkshire |
| Rapiteh Computer Services Ltd | |
| Rapport Ltd | Berkshire |
| Raptor | Merseyside |
| Rapyd Financial Network (2016) Ltd | Greater London |
| Rare Digital Marketing | South Yorkshire |
| Rare Form New Media | Oxfordshire |
| Rareloop Ltd | Hampshire |