| IWSA | Independent Washroom Services Association 
| Others |
| IWSA | Indian Women Scientists Association
| Others |
| IWSA | Indian Women Scientists' Association
| Others |
| IWSA | Indiana Water Ski Association
| Others |
| IWSA | Information Weighted Sequence Alignment
| Others |
| IWSA | Insurance Women of San Antonio
| Others |
| IWSA | Integrated Waste Services Association
| Others |
| IWSA | International WAGR Syndrome Association
| Others |
| IWSA | International Water Services Association
| Others |
| IWSA | International Water Supply Association
| Others |
| IWSA | International Winter Swimming Association
| Others |
| IWSA | International Woman Suffrage Alliance
| Others |
| IWSA | InterScan Web Security Appliance
| Others |
| IWSA | InterScanTM Web Security Appliance
| Others |