| Quad Computer Services Ltd | South Yorkshire |
| Quad Web | |
| Quadarc Multimedia | |
| Quadra Solutions Ltd | Lancashire |
| Quadram Institute | |
| QuadraNet Systems | Buckinghamshire |
| Qual Ltd | Surrey |
| Qualdesk | |
| QualitaX | |
| Quality Assurance Agency for Higher Education | |
| Quality Cartridge | Hertfordshire |
| Quality Clouds Ltd | |
| Quality Medical Solutions | Dorset |
| Quality Precision Electronics Ltd | Fife |
| Quality Training (Scotland) Ltd | Stirling |
| Quality Website Design UK | |
| Quant Insights Conference | |
| Quant Network Ltd | |
| Quanta Dialysis Technologies | |
| Quanta Dialysis Technologies Ltd | |
| Quanta Technology Ltd | Isle of Man |
| Quanta Training Ltd | Worcestershire |
| Quantek Ltd | Bedfordshire |
| Quantexa | |
| Quanticate | |
| Quantics Biostatistics | |
| Quantitative Investment Solutions Ltd | |
| Quantiv Ltd | Greater Manchester |
| QuantSoft | |
| Quantum | |
| Quantum CAD Ltd | Neath Port Talbot |
| Quantum Computing UK | |
| Quantum Digital Technologies | |
| Quantum Enterprise Developments Ltd | |
| Quantum Group | |
| Quantum Marketing Services Ltd | Surrey |
| Quantum Motion | |
| Quantum Motion | |
| Quantum Solutions Ltd | Isle of Man |
| Quantum Technology Club | |
| Quantum Technology Enterprise Centre | |
| Quantum.Tech | |
| QuantuMDx Group Ltd | |
| Quarks | Surrey |
| Quartix Ltd | Powys |
| Quasar Electronics Ltd | Hertfordshire |
| Quay Computer Services | |
| Quba | South Yorkshire |
| Qube Digital Media | |
| Qube Research & Technologies Ltd | |