CASI may refer to:
- Center for the Advanced Study of India, a center at the University of Pennsylvania
- Canadian Association of Snowboard Instructors
- CASI (test), a reading comprehension test in schools
- Center for AeroSpace Information, a center at NASA
- Cognitive Assessment Screening Instrument (CASI)
- Club Atlético San Isidro, a rugby club in San Isidro, Bueno Aires, Argentina
- Computer-assisted self interviewing
- Continental Air Services, Inc an airline
- Charitable Aviation Services International
- Cutting And Self Injury
- Compact Airborne Spectral Imager
- Chili Appreciation Society International
- Casi, also chashi, hilltop forts of the Ainu
- Casi, a supporting character from Ape Escape (series)