| Q*bert | The original 1982 Gottlieb Q*bert arcade machine, running in the browser on a from-scratch Intel 8088 core with an in-frame debugger. | online |
| Q-emuLator | Sinclair QL emulator for Windows and macOS by Daniele Terdina. | downloadable |
| QEMU | A generic open-source machine emulator and virtualizer supporting x86 PCs and many other architectures. | downloadable |
| QEMU (PowerPC Mac) | QEMU's g3beige and mac99 PowerMac machine models emulate PowerPC Macs running Mac OS 9 and early Mac OS X. | downloadable |
| QLay | Early Sinclair QL emulator for DOS and Windows by Jan Venema. | downloadable |
| QLay2 | Open-source Sinclair QL emulator descended from Jan Venema's QLay. | downloadable |
| QPC2 | Leading Windows Sinclair QL emulator and SMSQ/E platform by Marcel Kilgus. | downloadable |
| QUASI88 | High-performance open-source NEC PC-8801 emulator originally written by Showzoh Fukunaga. | downloadable |
| Qaop/JS | In-browser JavaScript ZX Spectrum emulator by Jan Bobrowski. | online |