IDT may refer to:
- Intelligent Design (Theory)
- Interdigital transducer, also called "interdigitated transducer", a sensor and transmitter for a surface acoustic wave
- Inactive Duty Training, the official military term for a weekend duty (or "drill periods") for U.S. Military Reservists and National Guardsman
- IDT An electronic band/production duo from Edinboro, PA
- Interrupt descriptor table, a memory structure of x86 microprocessors
- Israel Daylight Time
- Interactive Digital Technology, a workforce core technology group in animation, interactive web development, game development, virtual world development
- It Dies Today, a metalcore band from Buffalo, New York.
- Interior Design Technologist, Canadian Designation
- Insulation-displacement technology/termination, see insulation-displacement connector
Or one of the following companies:
- IDT Corp., a long-distance telephone carrier
- Integrated Device Technology, a semiconductor manufacturer
- Integrated DNA Technologies, the largest supplier of custom nucleic acids in the United States
- International Display Technology Ltd., a joint-venture of IBM and the Taiwanese Chi Mei group
- Integrated Display Technology, a Hong Kong based consumer electronics company.
- Innovative Defense Technologies, a Virginia based automated software testing company.