| Q | Charge; quality |
| q | Instantaneous charge |
| Q | Quality factor |
| QA | Quality Assurance |
| QAM | Quadrature Amplitude Modulation |
| QC | Quality Control |
| QCM | Quartz Crystal Microbalances |
| QFD | Quality Function Deployment |
| QFP | Quad Flat Pack |
| QFT | Quantum Field Theory |
| QHE | Quantum Hall Experiment |
| QML | Qualified Manufacturers List |
| QMS | Quadrupole Mass Spectroscopy |
| QPC | Quantum Point Contact |
| QPL | Qualified Products List |
| QPSK | Quadrature Phase Shift Keying |
| QSOP | Quarter Size Outline Package |
| QSR | Quality System Review |
| QTA | Quick Turn Around |
| QUAT-S | QUAdruple Transceiver for S/T Interface |
| QW | Quantum Well |
| QWIP | Quantum Well, Infra-Red (Photodetector) |
| QWIR | Quantum Well, Infra-Red (Detector) |
| QWR | Quantum Wire |
| QoS | Quality of Service |
