| Acronym | Meaning |
| GLP-1 | Glucagon-like Peptide 1 |
| GLRS | Grating Light Reflection Spectroscopy |
| GLS | Generalized Least Squares |
| GLSL | Green Light Stimulated Luminescence |
| GLT | Geochemical Logging Tool |
| GLWQA | Great Lakes Water Quality Agreement |
| GLWQB | Great Lakes Water Quality Board |
| GM | Geometric Mean |
| GMA | Glycidyl Methacrylate |
| GMAD | Geometric Mean Aerodynamic Diameter |
| GMAV | Genus Mean Acute Value |
| GMAW | Gas Metal Arc Welding |
| GMC | Giant Molecular Cloud |
| GMCC | Geophysical Monitoring For Climate Change |
| GMDH | Group Method Of Data Handling |
| GME | Generalized Master Equation (in Quantum Statistical Mechanics) |
| GMI | Giant Magnetoimpedance |
| GMISS | Gridded Model Information Support System |
| GMO | Generalized Molecular Orbital |
| GMO | Genetically Modified Organism |
| GMO | Group Molecular Orbital |
| GMP | Good Manufacturing Practice |
| GMP | Generalized Moeller-Plesset (perturbation Theory) |
| GMP | Guanosine 5'-monophosphate |
| GMP2 | Generalized Moeller-Plesset Second-order (perturbation Theory) |
| GMQDT | Generalized Multichannel Quantum Defect Theory |
| GMR | Giant Magnetoresistance |
| GMS | Glycerol Monostearate |
| GMT | Glass Mat Thermoplastic |
| GNACHO | Gravitationally Neg. Anomalous Compact Halo Object |
| GNLSE | Generalized Nonlinear Schroedinger Equation |
| GNMP | Generalized Nonlocal Model Potential |
| GNO | Geminal Natural Orbital |
| GNOME | GNU Object Modeling Environment |
| GNP | Gross National Product |
| GNRH | Gonadotropin Releasing Hormone |
| GNVP | Generalized Newton Variational Principle |
| GO | Gas Oil |
| GO | Gaussian Overlap (approxn. In Mol. Calcns.) |
| GO | Generalized Overlap |
| GO-SCF | Gaussian Orbital Self-consistent Field |
| GOCART | Georgia Tech/Goddard Global Ozone Chem. Aerosol Radiation And Transport Model |
| GOCE | Gaussian Overlap Potential With Const. Well Depth |
| GOCO | Government-owned |
| GOD | Glucose Oxidase |
| GODIVA | GOME Data Interpretation |
| GOE | Gaussian Orthogonal Ensemble (of Random Matrixes In Quantum Chaoticity Study In At. And Nuclear Energy Levels) |
| GOES | Geostationary Operational Environmental Satellite |
| GOEZS | Global Ocean Euphotic Zone Study |
| GOFS | Global Ocean Flux Study |