IRM may refer to:

• IERS Reference Meridian
• Illinois Railway Museum
• Illinois Reserve Militia, state defense force active during World War II
• Bureau of Information Resource Management, responsible for information technology of the U.S. Department of State
• Information Rights Management
• L'Institut Royal Météorologique de Belgique
• Interference reflection microscopy, a microscopy method used to image adherent cells
• Internal Revenue Manual, an official compendium of internal guidelines for personnel of the United States Internal Revenue Service
• International Review of Mission, a quarterly academic journal
• International Roaming MIN assigned by IFAST
• IRM (album), by Charlotte Gainsbourg
• Iron Mountain Incorporated, a data storage company based in Boston, Massachusetts
• ICAO designator for Mahan Air, an Iranian airline
• Islamic Republic of Mauritania