| Acronym | Meaning |
| ESML | Earth Science Markup Language |
| ESMR | Electronically Scanning Microwave Radiometer |
| ESN | ECS Science Network |
| ESNET | Energy Sciences Network |
| ESO | European Southern Observatory |
| ESPIRIT | European Strategic Programme For R&D In Information Technology |
| ESR | Electron Spin Resonance |
| ESRO | European Space Research Organization |
| ESS | Earth System Science |
| ESS | Engineering Equipment Surveillance System |
| ESSA | Environmental Science Services Administration |
| ESSC | Earth System Science Committee |
| ESSC | Environmental Science Services Administration |
| ESSCO | Electronic Space Systems Corporation |
| ESSCO | Environmental Science & Services Corporation |
| ESSIS | Earth System Science Information System |
| ESSL | Earth & Sun Systems Laboratory (formerly ATD) |
| ESTAR | Electrically Steered Thinned Array Radiometer |
| ESTEC | European Space Research And Space Technology Centre |
| ESTP | Exploratory Shaft Test Plan |
| ESTSC | Energy Science And Technology Software Center |
| ESU | Electrostatic Unit |
| ET | Evapotranspiration |
| ETA | A Vendor Of Supercomputers And Associated Software |
| ETA | A Hydrostatic Model That Employs The Eta Vertical Coordinate |
| ETA | A Subsidiary Of Control Data Corporation That Manufactures Supercomputers |
| ETAG | Educational Technologies Assistance Group |
| ETC | Estimate Time To Complete |
| ETC | Engineering Training Course |
| ETCE | Effects Of Tropical Convection Experiment |
| ETCO | External Tanks Corporation |
| ETE | Estimated Time En Route |
| ETEC | Energy Technology Engineering Center |
| ETFSP | Enhanced Technology Flight Segment Prototype |
| ETG | Eclipse Task Group |
| ETH | Eidgenossische Technische Hochschule |
| ETIP | Experimental Technology Incentive Program |
| ETL | Environmental Technology Laboratory |
| ETL | Energy Technology Programs |
| ETM | Enhanced Thematic Mapper |
| ETR | Element Test Review |
| ETS | Emergency Transponder System |
| EU | European Union |
| EUCLID | European Cooperation For The Long Term In Defense |
| EUCREX | European Cirrus Research Experimetn |
| EUMAC | Part Of EUROTRAC |
| EUMETSAT | European Meteorological Satellite |
| EURAM | European Research In Advanced Materials |
| EURATOM | European Atomic Energy Agency/Community |
| EUREKA | European Research Cooperation Agency |