Gef may refer to a supposed talking mongoose from the Isle of Man

Gef or GEF may also refer to:

• Global Enrichment Foundation, a Canadian humanitarian organization
• Global Environment Facility, an intergovernmental environmental organizations
• Global Equality Fund, of the United States Department of State
• Global Esports Federation, an international esports organization based in Singapore
• Green European Foundation, a European political foundation
• Greif, Inc., an American manufacturing company

• Graphical Editing Framework, a software framework
• Guanine nucleotide exchange factor, a group of proteins

• Greek Expeditionary Force (Korea), during the Korean War