MGY

MGY or a variant thereof is used as an abbreviation for:
 * Megagray (MGy) and milligray (mGy), SI derived units of the gray (absorbed radiation dose)
 * mgy, MGY, mmgy, MMgy, or MMGY: Million gallons per year

MGY as an identifier has been used to denote:
 * Dayton-Wright Brothers Airport, IATA code
 * Montgomeryshire, historic county in Wales, Chapman code
 * The maritime call sign of RMS Titanic's radiotelegraph station

MGY may also refer to:
 * MG Y-type, an MG car