IET
IET can refer to:

Organizations
Institute of Educational Technology, part of the Open University
Institution of Engineering and Technology, a UK-based professional engineering institution
Institute of Engineers and Technicians, which became part of the Institution of Incorporated Engineers in 1998 (which then became part of the Institution of Engineering and Technology in 2006)
Institute of Engineering and Technology of Lucknow, India
University Institute of Engineering and Technology, Kanpur University of Kanpur, India, formerly known as IET Kanpur
Institute of Engineering Technology, Sri Lanka, a Government higher education institute that providing NDES (National Diploma in Engineering Sciences) Award in Sri Lanka
IET Bhaddal, an engineering institute based in Bhaddal, Punjab
Islamic Educational Trust, Islamic organization in Nigeria
Institute of Engineering and Technology, Ayodhya of Faizabad, Uttar Pradesh, India

Persons
iET (musician), a singer-songwriter from the Netherlands

Processes
Impulse excitation technique
Initial Entry Training, the technical term for United States Army Basic Training
Interval exchange transformation
Interest Equalization Tax, an American tax initiative

Other
British Rail Class 800, British high-speed trains, known as Intercity Express Trains by their operator Great Western Railway
Indole-3-ethanol or tryptophol, a chemical compound