IED is a three-letter abbreviation which may refer to:

• Improvised explosive device, an explosive devices often used in unconventional warfare.
• Indo-European Etymological Dictionary, by Julius Pokorny
• Instantaneous electrical detonator
• Intermittent explosive disorder, an uncommon disorder of the brain.
• International Endowment for Democracy, a U.S. non-profit organization.
• Intelligent electronic device
• Immigration Employment Document, in the context of UK Immigration Documentation.