| Abbreviation | Definition |
|---|---|
| ISN | International Society of Nephrology |
| ISNS | International Society for Neoplatonic Studies |
| ISNTA | International Staple, Nail, and Tool Association |
| ISO | International Organization for Standardization |
| ISO | International Society of Organbuilders |
| ISO | International Sugar Organization |
| ISOB | International Society of Barristers |
| ISOT | Israel Society of Occupational Therapy |
| ISPA | International Software Process Association |
| ISPACA | The International Swimming Pool and Automatic Cover Association |
| ISPAN | Integrated Strategic Planning and Analysis Network |
| ISPAN | Internet Service Providers Association of Nepal |
| ISPAN | Internet Service Providers Association of Nigeria |
| ISPE | Idaho Society of Professional Engineers |
| ISPE | Illinois Society of Professional Engineers |
| ISPE | Indiana Society of Professional Engineers |
| ISPE | International Society for Pharmaceutical Engineering |
| ISPE | International Society for PharmacoEpidemiology |
| ISPE | International Society for Philosophical Enquiry |
| ISPE | International Society for Productivity Enhancement |