| Abbreviation | Definition |
|---|---|
| IODS | Indian Orthodox DiaSpora |
| IOK | International Order of Kabbalists |
| IOM | Internet Outreach Ministry |
| IONA | Islamic Organization of North America |
| IOP | Infant Of Prague Catholic Parish |
| IOR | Institute Of Religion |
| IOS | Individual Ordinance Summary |
| IP | Inspired People |
| IPBD | Interfaith Peace Builders Delegation |
| IPEN | International Presbyterian Education Network |
| IPHC | International Pentecostal Holiness Church |
| IPRC | Iglesia Presbiteriana Reformada del Caribe |
| IPT | Intercessory Prayer Team |
| IPUM | Information Project for United Methodists |
| IR | Islamic Religion |
| IRBC | Iowa Regular Baptist Camp |
| IRBS | Institute for Reformed Baptist Studies |
| IRBS | International Reformed Baptist Seminary |
| IRCS | Indian Rocks Christian School |
| IREF | India Rural Evangelical Fellowship |