| Acronym | Definition |
|---|
| ISTC | Illinois Sustainable Technology Center (Champaign, IL) |
| ISTC | International Science and Technology Center |
| ISTC | International Student Travel Confederation |
| ISTC | Indiana State Teachers College (Indiana and Pennsylvania) |
| ISTC | Institute of Scientific and Technical Communicators (UK) |
| ISTC | Independent Sector Treatment Centre (UK) |
| ISTC | International Standard Text Code |
| ISTC | International Space Training Center (Walt Disney World) |
| ISTC | International Standard Textual Work Code |
| ISTC | International SAMPE (Society for the Advancement of Material and Process Engineering) Technical Conference |
| ISTC | Integrated System Test Capability |
| ISTC | Institute of Swimming Teachers and Coaches Ltd (UK) |
| ISTC | International Shade Tree Conference |
| ISTC | International Science and Technology Conference |
| ISTC | Irish Society of Technical Communicators |
| ISTC | International Standard for Tuberculosis Care (medical treatment) |
| ISTC | International Special Training Center (Pullendorf, Germany; formerly International Long Range Reconnaissance Patrol School, ILRRPS) |
| ISTC | International Switching and Testing Center |
| ISTC | International Society of Tax Consultants |
| ISTC | Independent Sequential Track Correlation |
| ISTC | Integrated System Testing Center |