Leroi, or Leroy along with variant spellings and forms: Leroi, Le Roi or Roi is both a given name and a family surname of Norman origin.
Written interchangeably in records as: Roi, Roy, Le Roy, and De Roy, the surname Le Roi originated from the Normans, the descendants of Norse Vikings who settled in Amigny, a commune in Manche, Normandy. It derived from the Old French roy, roi (), meaning "king", or "the king" which was a byname used before the Norman Conquest and a personal name in the Middle Ages. The Normans, or "Northmen", after having settled in their new lands in Northern France, quickly adopted the Old French dialects of the region and would later take their language and naming practices with them to England.