| Abbreviation | Definition |
|---|---|
| IPPT | Intangible Personal Property Tax |
| IPR | Iowa Percentile Rank |
| IPSE | Indiana Partnership for Statewide Education |
| IRA | Irish Revolution Assistance |
| IRAD | Illinois Regional Archives Depository |
| IRBM | Integrated River Basin Management |
| IRGC | Iowa Racing and Gaming Commission |
| IRTC | Indianapolis Regional Transportation Council |
| IRV | Instant-Runoff Voting |
| ISAP | Immigrant Settlement Adaptation Program |
| ISAP | Invading Species Awareness Program |
| ISAR | Income Support Application Rejection |
| ISB | Iowa School Board |
| ISBA | Idaho State Board of Accountancy |
| ISBA | Islamic Speakers Bureau of Atlanta |
| ISBD | Idaho State Board of Dentistry |
| ISBE | Illinois State Board of Education |
| ISBE | Indiana State Board of Education |
| ISBEAR | Indiana State Board of Education Administrative Rules |
| ISBH | Illinois State Board of Health |