| Abbreviation | Definition |
|---|---|
| ISS | International Students Service |
| ISS | Introduction to Social Sciences |
| ISSEP | International Soros Science Education Program |
| ISSM | Indonesian Students Scientific Meeting |
| ISSM | International Student Services Management |
| ISSO | Social and Sustainable Oikonomics |
| ISSUP | Institute for Strategic Studies University of Pretoria |
| IST | Information Science and Technology |
| IST | Information Sciences Technology |
| IST | Institute of Space Technology |
| IST | Instituto Superior Tcnico (Technical Superior Institute) |
| IST | Instructional Support Team |
| IST | Instructional Systems Technology |
| IST | International Study Tour |
| ISTA | International Schools Theatre Association |
| ISTC | Illinois Sustainable Technology Center, University of Illinois |
| ISTY | Institut des Sciences et Techniques des Yvelines |
| ISU | Idaho State University |
| ISU | Illinois State University |
| ISU | Imam Sadiq University |