| Abbreviation | Definition |
|---|---|
| ISD | Investment Services Directive |
| ISDL | Interaction System Design Language |
| ISDP | Integrated Service Delivery Process |
| ISE | Internal Success Environment |
| ISEE | Integrity, Service, Enjoyment, and Excellence |
| ISFS | ICFAI school of Financial Studies |
| ISG | Industry Specific Group |
| ISG | Intermarket Surveillance Group |
| ISGP | Industrial Stormwater General Permit |
| ISI | Institutional Survivability Indicator |
| ISI | Integrity, Smartness, and Intellect |
| ISIN | International Securities Identification Number |
| ISIP | Initial Strategy Implementation Plan |
| ISIS | Industrial Sieves Inspection System |
| ISIS | Information Service Integration and Schooling |
| ISIS | Integrated Strategic Investment System |
| ISIS | Integrated Systems for Information Services |
| ISIS | Internet Service Information System |
| ISL | Innovation Service Loyalty |
| ISM | International Survey Member |