| Acronym | Definition |
|---|
| IRR | Iranian Rial (ISO currency code) |
| IRR | Internal Rate of Return |
| IRR | Individual Ready Reserve |
| IRR | Interest Rate Risk |
| IRR | Irregular |
| IRR | Internet Routing Registry |
| IRR | Inactive Ready Reserve |
| IRR | Institute for Religious Research (Grand Rapids, MI) |
| IRR | Implementing Rules and Regulations |
| IRR | Institute of Race Relations (UK) |
| IRR | Integra Realty Resources (New York, NY) |
| IRR | Initial Return Rate |
| IRR | Infra Red Remote |
| IRR | Interracial Relationship |
| IRR | Independent Race and Refugee (news network; Institute of Race Relations) |
| IRR | Intermediate Ring Road (India) |
| IRR | Interrupt Request Register |
| IRR | Indiana Rail Road |
| IRR | Integral Rocket Ramjet (propulsion system) |
| IRR | Inspection Rejection Report |
| IRR | International Radio Regulations (various locations) |
| IRR | Ionising Radiations Regulations |
| IRR | Image Rejection Ratio |
| IRR | Information Request Response |
| IRR | In-Plan Roth Rollover (tax device) |
| IRR | Investigative Records Repository |
| IRR | Integrative Research Review (methodology) |
| IRR | Infrared Reflectography |
| IRR | Integrated Readiness Report (US DoD) |
| IRR | Initial Response Resources |
| IRR | Integrated Resource Recovery |
| IRR | Individual Retirement Record |
| IRR | Implementation Readiness Review |
| IRR | Institute of Resource Recovery |
| IRR | Integrated Radio Room |
| IRR | Internal Recall Recorder (Telex Vega) |
| IRR | Interface Requirements Review |
| IRR | Infra-red Radiometer |
| IRR | Immediate Reroute |
| IRR | Initial Requirements Review |
| IRR | Ionizing Radiations Regulations |
| IRR | Initial Return Rate (TL 9000) |
| IRR | Intelligence Radar Reporting |
| IRR | Interim Research Review |
| IRR | Independent Referencing Review |
| IRR | Integral Rocket Engine |
| IRR | Iron Road Railways, Inc. |
| IRR | Inspect and Repair as Required |
| IRR | Institute for the Recovery from Racisms |
| IRR | Installation Readiness Report |
| IRR | Infusion-Related Reaction |
| IRR | Investment Return Ratio (economics) |
| IRR | Issues Relating to Research |
| IRR | Interference Reduction Ratio |