ISCA
- ISCABBS
- Indian Science Congress Association
- Institute of Singapore Chartered Accountants
- International Scouting Collectors Association
- International Sea Cadet Association
- International Society of Caricature Artists
- International Society of Copier Artists
- International Speech Communication Association
- International Sport and Culture Association
- International Symposium on Computer Architecture
- Isca Academy
- Isca Augusta
- Isca Dumnoniorum
- Isca Hockey Club
- Isca Marina
- Isca sullo Ionio
- Iscah
- Iska (disambiguation)
- Islamic Supreme Council of America
- Israeli Students Combating Antisemitism
- Meteș