Leonard Calvert (1606 – June 9, 1647) is the First Proprietary Governor of Maryland.

He is the second son of George Calvert, 1st Baron Baltimore, (1579-1632), the first proprietary of the Province of Maryland.

His elder brother Cecil, (1605-1675), who inherits the colony and the title upon the death of their father George, April 15, 1632, appoints Leonard as governor of the Colony in his absence.

Leonard is named after his grandfather, the father of George who was also "Leonard Calvert" of Yorkshire.