| Abbreviation | Definition |
|---|---|
| IBSA | International Bilingual Schools of Africa |
| IBSB | International British School of Bucharest |
| IBSL | International Bilingual School Ljubljana |
| IBST | International Business School Tuttlingen |
| IBSU | International Business School Union |
| IBTI | International Bible Training Institute |
| ICAS | International Competition Assessments for Schools |
| ICAS | International Competitions and Assessment for Schools |
| ICAS | International Competitions and Assessments for Schools |
| ICCR | Immaculate Conception Catholic Regional School |
| ICCS | Immaculate Conception Cathedral School |
| ICCS | Indiana Cyber Charter School |
| ICE | In-Class Essay |
| ICGS | Immaculate Conception Grade School |
| ICHS | Ilemopo Comprehensive High School |
| ICHS | Illiana Christian High School |
| ICHS | Independence Continuation High School |
| ICHS | International Christian High School |
| ICHS | International Community High School |
| ICHS | Island Coast High School |