ITD may refer to: Income Tax Department, Government of India's department for direct taxes Idaho Transportation Department Impedance threshold device, a valve used in cardiopulmonary resuscitation (CPR) Information Technology Directorate (formerly the Information Engineering Directorate) of the United Kingdom government Department of Trade and Industry Inter-type declaration, a feature of Aspect-oriented computer programming. Interaural time difference, the difference in arrival time of a sound between two ears Internal tandem duplication, a form of mutation (see gene duplication and tandem exon duplication)