Baron Baltimore is a defunct title in the Peerage of Ireland. The barony was created in 1625 and became extinct following the death of the sixth baron in 1771. The title was held by several members of the Calvert family who were the proprietors of the Province of Avalon in Newfoundland and the Province of Maryland, later the U.S. state of Maryland.

In the context of United States history, the name Lord Baltimore usually refers to Cæcilius Calvert, 2nd Baron Baltimore after whom the city of Baltimore, Maryland is named. His younger brother Leonard Calvert was the first Governor of Maryland. See also: Province of Maryland.

Barons Baltimore (1625)

• George Calvert, 1st Baron Baltimore
• Cæcilius Calvert, 2nd Baron Baltimore
• Charles Calvert, 3rd Baron Baltimore
• Benedict Leonard Calvert, 4th Baron Baltimore
• Charles Calvert, 5th Baron Baltimore
• Frederick Calvert, 6th Baron Baltimore