ISF may stand for:
Science and technology Imaging Science Foundation 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
International Stabilization Force, military force in Gaza.
Idaho Shakespeare Festival, theater company Importer Security Filing Impôt de Solidarité sur la Fortune, a French wealth tax Indian Secular Front, an Indian political party 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