| IASA | Association Internationale d'Archives Sonores et Audiovisuelles 
| Others |
| IASA | Idaho Association of School Administrators
| Others |
| IASA | IETF Administrative Support Activity
| Others |
| IASA | Illinois Association of School Administrators
| Others |
| IASA | Improving America's Schools Act
| Others |
| IASA | India Association of San Antonio
| Others |
| IASA | Indian American Student Association
| Others |
| IASA | Insurance Accounting and Systems Association
| Others |
| IASA | Internal Audit Student Association
| Others |
| IASA | International Aeronautics and Space Agency
| Others |
| IASA | International American Student Alliance
| Others |
| IASA | International American Studies Association
| Others |
| IASA | International Association for the Study of Attachment
| Others |
| IASA | International Association of Software Architects
| Others |
| IASA | International Association of Sound and Audiovisual
| Others |
| IASA | International Association of Sound and Audiovisual Archives
| Others |
| IASA | International Aviation Safety Assessment
| Others |
| IASA | Internationale Vereinigung der Schall- und audiovisuellen Archive
| Others |
| IASA | Interruptable As Soon As
| Others |
| IASA | Interruptible As Soon As
| Others |
| IASA | Interuptable As Soon As
| Others |
| IASA | Irish Amateur Swimming Association
| Others |
| IASA | Irish Aviation Students Association
| Others |
| IASA | Israel Arts and Science Academy
| Others |
| IASA | Italian American Studies Association
| Others |