| Abbreviation | Definition |
|---|---|
| IRTA | Illinois Retired Teacher's Association |
| IRTC | International Rolling Technology Course |
| IRTC | Internet Resources for Technical Communicators |
| IRTE | Institute for Road Traffic Education |
| IRWIL | I Read What I Like |
| ISA | Integrity, Soul, and Attitude |
| ISA | Investigative Skills Assessment |
| ISAEP | Individual Student Alternative Education Plan |
| ISATA | Idaho Speech Arts Teacher's Association |
| ISBE | International Society of Business Education |
| ISBP | Inter-generational School Breakfast Program |
| ISCA | Illinois School Counselor Association |
| ISCA | Indiana School Counselor Association |
| ISCE | International Studies in Catholic Education |
| ISCED | International Standard Classification of Education |
| ISCED | International Standard Classification of Education Designed |
| ISCED | International Standard Classification of Education developed |
| ISCL | Interdependent Self Cooperative Learning |
| ISD | Independent School District |
| ISD | Intermediate School District |