IRR

• Image rejection ratio
• Implied repo rate
• Incidence rate ratio
• Incident Response Regiment (Australia)
• Individual Ready Reserve
• Infusion-related reaction
• Inner Ring Road (disambiguation)
• Institute for Religious Research
• Institute of Race Relations
• Inter-rater reliability
• Interest rate risk
• Internal rate of return
• Internet Routing Registry
• Interrupt Request Register
• Iranian rial
• Iraqi Republic Railways
• Irregular galaxy
• South African Institute of Race Relations