IED
IED may refer to:

Devices
Improvised explosive device, an explosive device often used in unconventional warfare
Instantaneous electrical detonator, used to trigger an explosive device
Intelligent electronic device, in the electric power industry
Implantable electronic device, pacemaker

Dictionaries
Indo-European Etymological Dictionary
Indogermanisches etymologisches Wörterbuch (Indo-European Etymological Dictionary), by Julius Pokorny
Interlingua–English Dictionary, the first major presentation of Interlingua to the public

Healthcare
Inter-ictal epileptiform discharge, a characteristic of epileptic seizures
Intermittent explosive disorder, a mental health disorder
Intestinal epithelial dysplasia, another name for congenital tufting enteropathy

Organizations
Information Engineering Directorate, Information Technology Directorate of the UK Department of Trade and Industry
Institute for Educational Development, at Aga Khan University
Institute of Economic Development
Institution of Engineering Designers, in the UK
Istituto Europeo di Design, European Institute of Design
NASU Institute of Electrodynamics, a research institute in Kyiv

Other uses
Industrial Emissions Directive, a European Union directive
Infliction of Emotional Distress, a tort cause of action, falling under intentional torts