English abbreviations from ist to isyscon
- IST (Information System Technology)
- ISTA (International Safe Transit Association)
- ISTAR (Intelligence, Surveillance, Target Acquisition, and Reconnaissance)
- ISTC (Institute of Scientific and Technical Communications (UK))
- ISTE (International Society for Technology in Education)
- ISTeC ((organization) International Small Telescope Cooperative)
- ISTQB (International Software Testing Qualifications Board)
- ISTS (Intel Science Talent Search)
- ISTY (Institut des Sciences et Techniques des Yvelines)
- ISU (Integrated Sight Unit)
- IS-U (Industry Specific for Utilities)
- ISUP (International Summer University Program)
- ISURP (Iowa State University Research Park)
- ISV (Independent Software Vendor)
- ISW (South Wood County Airport (Alexander Field))
- ISWAK (It Started With A Kiss)
- ISY ((observing program/meeting) International Space Year, the name given to a celebration of space exploration as well as a series of coordinated astronomical observations and a series of meetings to plan future astronomy research efforts)
- ISYE (School of Industrial and Systems Engineering)
- ISYSCON (Information System Control)