| IFSO | Insurance and Financial Services Ombudsman 
| Others |
| IFSO | Integrated Family Service Organization
| Others |
| IFSO | International Faculty Scholar Office
| Others |
| IFSO | International Faculty Scholars Office
| Others |
| IFSO | International Family Support Organization
| Others |
| IFSO | International Federation for Sport Officials
| Others |
| IFSO | International Federation for Sports Officials
| Others |
| IFSO | International Federation for the Surgery of Obesity
| Others |
| IFSO | International Flight Safety Officer
| Others |
| IFSO | International Fun Science Olympiad
| Others |
| IFSO | Irish Free Software Organisation
| Others |