| Acronym | Definition |
|---|
| IAO | Fraunhofer-Institut für Arbeitswirtschaft und Organisation |
| IAO | It's All Over (various organizations) |
| IAO | International Affairs Office (various organizations) |
| IAO | In And Out |
| IAO | Information Awareness Office |
| IAO | Input Analysis Output |
| IAO | Indian Astronomical Observatory |
| IAO | Information Awareness Office (US DARPA) |
| IAO | Information Assurance Officer |
| IAO | Incorporated Association of Organists (UK) |
| IAO | Individual Artists of Oklahoma (Oklahoma City, OK) |
| IAO | International Astronomy Olympiad |
| IAO | International Accreditation Organization |
| IAO | Individual Assistance Officer |
| IAO | Isis Apophis Osiris (alchemical formula) |
| IAO | Information Asset Owner (UK) |
| IAO | International Association for Orthodontics |
| IAO | Isomerized Alpha Olefin (oil) |
| IAO | International Affairs Organization (various locations) |
| IAO | Industry Alliances Office |
| IAO | Instituto Agronomico per l'Oltremare (Italy) |
| IAO | International Announcement of Opportunity |
| IAO | I Am Outtahere |
| IAO | Irish Association of Orthoptists (vision; Ireland) |
| IAO | Improvise, Adapt, Overcome |
| IAO | Institute for Archaeological Oceanography |
| IAO | Institutional Affairs Office |
| IAO | Information Activities Office(r) |
| IAO | Interim Approval to Operate |
| IAO | Industrial Applications Office |
| IAO | Inter-Agency Committee on Oceanography |
| IAO | Independent Artists of Oklahoma |
| IAO | I Am Online |
| IAO | Integrated Operations Architecture |
| IAO | Information and Computer Science (ICS) Alumni Organization (University of California, Irvine) |