DET or Det may refer to:

  • Detroit (Amtrak station); Amtrak station code DET
  • Coleman A. Young International Airport, formerly Detroit City Airport, IATA Code DET
  • Diethyltryptamine, a psychedelic drug
  • Detection error tradeoff
  • It (Christensen book), a book of poetry by Inger Christensen, with the original title Det
  • The mathematical determinant
  • Department of Education and Communities (New South Wales), formerly the Department of Education and Training (DET)
  • 14 Intelligence Company, an alleged covert intelligence unit of the British Army in Northern Ireland, known as "The Det"
  • Detective (abbreviation)