Benedict Leonard Calvert, 4th Baron Baltimore (March 21 1679- April 16 1715) was the second son of Charles Calvert, 3rd Baron Baltimore and became his father's heir upon the death of his elder brother, Cecil in 1681. He married Lady Charlotte Lee, daughter of the Earl of Litchfield and they had seven children.

Calvert's father had lost title to the Province of Maryland due to the Glorious Revolution. Benedict Leonard attempted to have the title restored by renouncing Roman Catholicism and joining the Church of England. He was subsequently elected to the House of Commons as Member of Parliament for Harwich, Essex.

His father was angered by Benedict Leonard's desertion of the Catholic faith and cut off his son's allowance.

He became the 4th Baron Baltimore upon the death of his father in February 1715 and immediately petitioned King George I of England for the restoration of Maryland to his control, however, before the King could rule on the petition Calvert died. Shortly after his death the King restored title to Maryland to Calvert's son, Charles who had become the 5th Baron Baltimore.