| Abbreviation | Definition |
|---|---|
| ISCM | International Society of Contemporary Music |
| ISCS | Idaho State Civic Symphony |
| ISGM | International School of Gospel Music |
| ISIM | International Society for Improvised Music |
| ISIS | Intelligent Sisters In Step |
| ISL | Inner Self Lost |
| ISM | Incorporated Society Of Musicians |
| ISM | Intelligent System of Music |
| ISMC | Iowa Summer Music Camps |
| ISME | International Society for Music Education |
| ISMF | International Spanish Music Festival |
| ISMFOF | I Set My Friends On Fire |
| ISMIR | International Society for Music Information Retrieval |
| ISMIR | International Society of Music Information Retrieval |
| ISMN | International Standard Music Number |
| ISMS | Intelligent Sound And Music Systems |
| ISO | Indianapolis Symphony Orchestra |
| ISOA | Indianapolis Symphony Orchestra Association |
| ISTBE | I Sing The Body Electric |
| ISTS | I Shot the Sheriff. |