IMR
- IMR vessel
- Ideomotor response
- Immediate mode (computer graphics)
- Imperial Military Railways
- Improved military rifle powder
- In Medias Res (band)
- Individual ministerial responsibility
- Industrija Motora Rakovica
- Infant mortality rate
- Institute for Materials Research
- Institute of Marine Research
- Institutional mode of representation
- Interlocking machine room
- International Marketing Review
- International Migration Review
- International Mineral Resources
- Interrupt mask register
- Inverse Mills ratio
- Isle of Man Railway
- T-55