SFG

SFG may refer to:

Military

 * Special Forces Group (Belgium)
 * Special Forces Group (Japan)
 * Special Forces (United States Army)

Science and Technology

 * Sum-frequency generation in optical physics
 * Signal-flow graph
 * Superior frontal gyrus, in the human brain
 * Systemic functional grammar

Other

 * San Francisco Giants, a Major League Baseball team
 * L'Espérance Airport, IATA airport code