John Montgomery (1764 – July 17, 1828) was an American lawyer from Baltimore, Maryland. He represented the sixth district of Maryland in the U.S. Congress from 1807 until 1811. He served as the Attorney General of Maryland from 1811 to 1818 and Mayor of Baltimore from 1820 to 1822 and 1824 to 1826.
The son of John Montgomery, a member of the Continental Congress during the American Revolution, the younger John Montgomery was born in Carlisle, Pennsylvania in 1764. He was educated in Carlisle, studied law, was admitted to the bar in 1791 and moved to Harford County, Maryland to begin a practice.
A Democratic-Republican, Montgomery served in the Maryland House of Delegates from 1793 to 1798. From 1793 to 1796 he was Harford County's State's Attorney.
In 1806 Montgomery was a successful candidate for Congress. He won reelection in 1808 and 1810, and served in the 10th, 11th, and 12th Congresses, holding office from March 4, 1807 until he resigned on April 29, 1811.
Montgomery resigned from Congress and relocated to Baltimore in order to accept appointment as Attorney General of Maryland. He served from April 29, 1811 to February 11, 1818.