AET may refer to:

• Academies Enterprise Trust, in the UK
• Actual Evapotranspiration, in climatology
• Administration for Technical Investigations (Administration des enquêtes techniques)
• Aerobic exercise training
• AET (company), a shipping company formerly known as American Eagle Tankers
• Aet (given name), an Estonian feminine given name
• Affective Events Theory, a model developed by organizational behaviorists to identify how emotions and moods influence job performance and satisfaction
• "After extra time", in sports, the score after overtime has finished
• All-electronic tolling
• Allakaket Airport in Alaska (IATA Code: AET)
• American Educational Trust, a non-profit foundation
• Application Entity Title, in the DICOM medical imaging standard
• Assistant English Teacher, also called an Assistant Language Teacher
• Australian Eastern Time, a time zone in Australia
• Award in Education and Training, in UK education
• S-(2-aminoethyl)isothiuronium bromide hydrobromide
• α-Ethyltryptamine, a psychoactive drug belonging to the tryptamine family