WSI

The acronym WSI may refer to:


 * Wafer-scale integration, a technique for building large integrated circuits
 * Wall Street Institute, the former name of Wall Street English, an English language education company
 * Walter Schottky Institute, a research center at the Technical University of Munich
 * Water Safety Instructor, a person qualified to teach swimming lessons
 * Weather Services International, a sister company to The Weather Channel, specializing in weather data and software
 * Weather Stress Index, a relative measure of weather conditions
 * Web Services Interoperability, Organization (WS-I), computer industry consortium
 * Western Sydney Airport – the IATA code of this under-construction airport in Sydney
 * Western Sydney Institute of TAFE, college institute in New South Wales
 * Winter Soldier Investigation, inquiry into war crimes resulting from United States policies in the Vietnam War
 * Wojskowe Służby Informacyjne, Poland's former military intelligence services
 * World Security Institute, think-tank for independent research and journalism on global affairs
 * World Sindhi Institute, a human rights organization based in Washington, D.C., United States
 * Wrimare School Inc., a private school in Obando, Bulacan, Philippines
 * Written Scheme of Investigation, a document outlining a property developer's obligation to conduct archaeological research in England's planning system
 * Whole Slide Imaging, refers to scanning a complete microscope slide and creating a single high-resolution digital file.