IRP
- Field ration
- I/O request packet
- Indianapolis Raceway Park
- Initiative of the Republic of Poland
- Institute of Revolutionary Practice
- Integrated Rail Plan for the North and Midlands
- Integrated Resource Plan
- Integrated resource planning
- International Recovery Platform
- International Registration Plan
- International Reporting Project
- International Resource Panel
- Iron-responsive element-binding protein
- Irpinian dialect
- Islamic Renaissance Party of Tajikistan
- Islamic Republic Party
- Islamic Republic of Pakistan
- Matari Airport
- NIH Intramural Research Program
- Schlesinger Institute