IBS
- Brier score
- Broken News
- Ichthyosis bullosa of Siemens
- Ideal body size
- Identical by state
- Iman Budhi Santosa
- Industrialised Building System (IBS)
- Institute for Basic Science
- Institute for Structural Research
- Institute of Bangladesh Studies
- Institute of Broadcast Sound
- Integrated bridge system
- Intercollegiate Broadcasting System
- International Bible Society
- International Bilingual School
- International Biometric Society
- International Boy Scouts, Troop 1
- International Boys' Schools Coalition
- International Builders' Show
- International Business School, Budapest
- International Business School, Germany
- International Business Systems
- Internet Broadcasting
- Intrabeam scattering
- Iowa Braille School
- Iron-based superconductor
- Irritable bowel syndrome
- Isaac Bashevis Singer
- Israel Broadcasting Service
- LuckyFM Ibaraki Broadcasting System
- Plainfield Juvenile Correctional Facility
- Sputter deposition
- The Wire