DET or Det may refer to:
Education Department of Education (New South Wales), formerly Department of Education and Training Duolingo English Test (DET), a standardized language test
Mathematics Detection error tradeoff det, mathematical notation for the determinant of a matrix
Places Detroit, Michigan, United States Detroit (Amtrak station) Coleman A. Young International Airport, Detroit (IATA:DET)
Sport Sports in Detroit, US Detroit Lions, National Football League Detroit Pistons, National Basketball Association Detroit Tigers, Major League Baseball Detroit Red Wings, National Hockey League
Other uses Dafydd Elis-Thomas (1946-2025), Welsh politician Determiner, in interlinear glossing Diethyltryptamine, a psychedelic drug It (poetry collection), 1969, by Inger Christensen () 14 Intelligence Company "The Det", a British undercover military unit Disney Entertainment Television, the TV broadcasting division of The Walt Disney Company