ISF

ISF may stand for:

Science and technology

 * Imaging Science Foundation
 * Impulse sensitivity function
 * Incremental sheet forming
 * Information Security Forum, an international information security best practices organization
 * Ingenieurs Sans Frontieres (Engineers Without Borders)
 * Ink Serialized Format, a vector image file format from Microsoft
 * Interstitial fluid
 * Israel Science Foundation

Education

 * Idries Shah Foundation, educational charity
 * Independent Schools Foundation Academy, private international school in Hong Kong
 * Insaf Student Federation, it is the largest Center-Left Student organization in the Nation and the official student wing of the Pakistan Tehreek-e-Insaf political party
 * International School of Florence
 * International School Sport Federation, sports governing body for high school sport
 * Internationale Schule Frankfurt Rhein-Main

Sport

 * International Snowboard Federation
 * International Softball Federation
 * International Skyrunning Federation, world sports governing body for skyrunning
 * International Socca Federation, governing body of small-sided-football
 * International Sumo Federation, governing body for amateur sumo

Other

 * Idaho Shakespeare Festival, theater company
 * Importer Security Filing
 * Impôt de Solidarité sur la Fortune, a French wealth tax
 * Indian Secular Front
 * Information Support Force, a service branch of the People's Liberation Army
 * Internal Security Forces, of Lebanon
 * International Seafarers' Federation, former international trade secretariat
 * Iraqi security forces
 * Italian Strategic Fund
 * Lexus IS F