| Abbreviation | Definition |
|---|---|
| INSF | Intelligence and National Security Foundation |
| INSF | Iran National Science Foundation |
| IOCF | International Organic Chemistry Foundation |
| IOF | International Olive Foundation |
| IOF | International Osteoporosis Foundation |
| IOTF | Internet of Things Foundation |
| IPAF | Intellectual Property Awareness Foundation |
| IPEF | Indian Prairie Educational Foundation |
| IPF | Independence Pass Foundation |
| IPLF | Iran Public Libraries Foundation |
| IPPF | International Penal and Penitentiary Foundation |
| IPRF | Illinois Park and Recreation Foundation |
| IPRF | Illinois Park Recreation Foundation |
| IPRF | Innovative Pavement Research Foundation |
| IPRF | International Pediatric Research Foundation |
| IRC | Islamic Research Center (Pakistan) |
| IRCF | Icelandic River Community Foundation |
| IRCF | International Reptile Conservation Foundation |
| IREF | Islamic Research and Educational Foundation |
| IREF | Island Radio Expedition Foundation |