ESF may stand for:
- Esperantic Studies Foundation
- Empowering Spirits Foundation
- Enterprise System Frame by Visionet Systems
- European Science Foundation
- European Social Forum
- European Social Fund
- European Studbook Foundation
- European Students' Forum (or AEGEE), one of Europe's largest, cross-faculty student organisations
- State University of New York College of Environmental Science and Forestry (SUNY-ESF)
- Ecoles Sans Frontières, a non-governmental organization
- Emergency Support Function, subject-specific areas of the U.S. Federal Emergency Management Agency's response plans
- English Schools Foundation, an organization of twenty Hong Kong schools
- Earth's Special Forces, a Half-Life mod based on Dragonball Z
- Exchange Stabilization Fund, an emergency reserve fund of the United States Treasury Department
- Extended Super Frame, a line framing standard used in T1 telephony lines
- Exatron Stringy Floppy, an 8-bit computer peripheral