IMB is a three-letter abbreviation that may refer to:
- IMB Banking & Financial Services, Australian banking institution
- Independent Monitoring Board, a group of officials who monitor and report on the conditions in which prisoners are held in English and Welsh jails
- the former New York Stock Exchange stock symbol for Indymac Bancorp, the parent company of Indymac Bank, Pasadena, California
- Insect Molecular Biology, a scientific journal.
- Institute of Marine Biosciences, part of the National Research Council of Canada
- Institute of Molecular Biology in Mainz, Germany
- The Institute for Molecular Bioscience, a research institute at The University of Queensland, Australia
- Integrated Media Block, a component in a digital cinema projection system
- Integrated Mobile Broadcast, a technology for MobileTV application using 3G/4G networks
- Intelligent Mail Barcode, a 65-bar code applied to mail in the United States.
- Intermenstrual bleeding
- The International Maritime Bureau, a specialised bureau of the International Chamber of Commerce
- The International Mission Board of the Southern Baptist Convention
- Irish Medicines Board, the Irish authority for pharmacovigilance reporting
- The Irvine-Michigan-Brookhaven detector, a nucleon decay detector and neutrino observatory in Ohio