| Acronym | Definition |
|---|
| IRS➣Internal Revenue Service (US government) |
| IRS➣Insulin Receptor Substrate |
| IRS➣Indoor Residual Spraying (mosquito control) |
| IRS➣Independent Rear Suspension |
| IRS➣Interest Rate Swap |
| IRS➣Insulin Receptor Signaling |
| IRS➣Indian Remote Sensing Satellite |
| IRS➣Infrared Spectrograph |
| IRS➣Image Retrieval System (computing) |
| IRS➣Insulin Resistance Syndrome |
| IRS➣Institut für Raumfahrtsysteme (German: Institute of Space Systems) |
| IRS➣Information Retrieval System |
| IRS➣InfoFrame Relational Store (NEC Corporation) |
| IRS➣Indian Register of Shipping (Indian ship classification society) |
| IRS➣Internal Rating System (finance) |
| IRS➣Infra Red Sensor |
| IRS➣International Retail Service |
| IRS➣Internal Revenue Service |
| IRS➣Interchange Record Separator |
| IRS➣Initial Receive Sequence |
| IRS➣Imposto Sobre o Rendimento das Pessoas Singulares (Portuguese tax) |
| IRS➣Immune Reconstitution Syndrome |
| IRS➣Interactive Response System (educational remote control) |
| IRS➣Indus River System |
| IRS➣Information Required Schedule (project planning) |
| IRS➣Iron Replacement System (golf) |
| IRS➣Inertial Reference System |
| IRS➣Investment Research Service |
| IRS➣Incident Reporting System |
| IRS➣Interface Requirements Specification |
| IRS➣Information Referral Services (Ontario, Canada) |
| IRS➣Information Reporting System |
| IRS➣Increasing Returns to Scale |
| IRS➣Information and Referral Specialist (various organizations) |
| IRS➣Indian Revenue Service (India) |
| IRS➣Investor Relations Society |
| IRS➣Interpreter Referral Service (various organizations) |
| IRS➣International Register of Shipping (est. 1993; shipping industry) |
| IRS➣Inventory Reduction Sale |
| IRS➣Irwin R. Schyster (pro wrestler) |
| IRS➣Internal Review Service (UK) |
| IRS➣Identical, Related and Similar (US DHHS) |
| IRS➣Improved Rain Suit (US Air Force) |
| IRS➣International Radar Symposium |
| IRS➣Institute of Regional Studies (Pakistan government) |
| IRS➣Intelligence Research Specialist (FBI) |
| IRS➣Integrated Resorts Scheme (Mauritius) |
| IRS➣Intra Renal Surgery |
| IRS➣Integrated Receivables Solutions (banking) |
| IRS➣Informal Resolution System |
| IRS➣Insurance Restoration Services, Inc. (New Jersey) |
| IRS➣International Referral System (now INFOTERRA) |
| IRS➣Inherited Runners Scored (baseball; runner on base who scores after a new pitcher enters) |
| IRS➣Intel Research Seattle |
| IRS➣International Rorschach Society |
| IRS➣Illinois Radiological Society |
| IRS➣Interest Rate Support |
| IRS➣Independent Recyling Services |
| IRS➣Infrared Locking System (automobiles) |
| IRS➣Internationally Recruited Staff |
| IRS➣Intermediate Reference System |
| IRS➣International Research and Studies Program (US) |
| IRS➣Intelligent Register System (Q.I. Press Controls) |
| IRS➣individual replacement system (World War 2 troop rotation) |
| IRS➣Industrial Relations Survey (UK) |
| IRS➣Immunoreactive Remmele Score (cancer) |
| IRS➣Information Receiving Station |
| IRS➣Infrared Soldering |
| IRS➣Interstate Repeater Society |
| IRS➣Ionizing Radiation Standards Group (National Research Council of Canada, Ottawa, Canada) |
| IRS➣I'll Return Shortly |
| IRS➣Ignition Radiation Suppression |
| IRS➣Interdisciplinary Research Support (various schools) |
| IRS➣Incident Response Service |
| IRS➣Inland Refugee Society (Vancouver, British Columbia, Canada) |
| IRS➣Indian Remote Sensing System |
| IRS➣Index of Retail Saturation |
| IRS➣International Reference Star (set of star catalogs) |
| IRS➣Interferometric Rayleigh Scattering |
| IRS➣Item Reduction Study |
| IRS➣Input Record Seperator (Perl programming language) |
| IRS➣Imagery Requirements Structure |
| IRS➣Increasing Radius Search |
| IRS➣Individual Readiness Survey (education) |
| IRS➣Infrastructure Requirements Specification |
| IRS➣Interference Reduction System |
| IRS➣Indefinite Reserve Status |
| IRS➣Indiana Railroad System |
| IRS➣Institute of Railway Signal Engineers (UK) |
| IRS➣Infrared Suppressor |
| IRS➣Installation Readiness System |
| IRS➣Institute for Reactor Safety, Germany (now Gesellschaft für Anlagen- und Reaktorsicherheit mbH) |
| IRS➣Induction and Recruiting Station |
| IRS➣Integrated Resource and Schedule |
| IRS➣International Racing System |
| IRS➣Integrated Reconstructed Spectrum |
| IRS➣International Russian Society |
| IRS➣Integrated Review Software |
| IRS➣Impulse Radio Sequence |
| IRS➣Inferno Reckless Summonn (Yu-Gi-Oh) |
| IRS➣Individual Research Study |
| IRS➣International Reply Service |
IRS - the bureau of the Treasury Department responsible for tax collections