| IISA | Imperial International Sports Academy 
| Others |
| IISA | Information Intelligence Systems and Applications
| Others |
| IISA | Institute for Islamic Strategic Affairs
| Others |
| IISA | Insurance Institute of South Africa
| Others |
| IISA | International Ice Swimming Association
| Others |
| IISA | International Independent Showmens Association
| Others |
| IISA | International Indian Statistical Association
| Others |
| IISA | International Indoor Soccer Arena
| Others |
| IISA | International Inline Skating Association
| Others |