| Acronym | Definition |
|---|
| ISAO | Information Sharing and Analysis Organization |
| ISAO | Internationale Stichting Alzheimer Onderzoek (Netherlands) |
| ISAO | International Society for Artificial Organs (est. 1977) |
| ISAO | International Society of Arboriculture Ontario (Canada) |
| ISAO | International and Study Abroad Office (university program) |
| ISAO | International Student Advising Office (Nashua, NH; Rivier College) |
| ISAO | International Symposium on Aquatic Oligochaeta |
| ISAO | International Student Affairs Officer (University of California, Riverside) |