Jacob Jennings Brown (May 9, 1775-February 24, 1828) was an American army officer in the War of 1812.

Born in Bucks County, Pennsylvania, he was the son of Samuel and Abi (White) Brown. Raised a Quaker, he was graduated from the University of Pennsylvania in 1790. He taught school and in 1798 moved to upstate New York.

When the War of 1812 began, he was brigadier general in the New York militia. Though he opposed the war, he organized the defenses in the Great Lakes region. He defeated the British at the Battle of Sackett's Harbor on May 29, 1813. The next year his army captured Fort Erie in Ontario. He was wounded twice at the Battle of Lundy's Lane, one of the bloodiest of the war for both sides. His successes in the northwest made him a national hero.

After the war, the Army was cut and in 1821, he was the only major general in the service. President James Monroe made him commanding general of the army, but he was unable to do much in the post because of a stroke. He died in Washington, D.C..

Brown County, Ohio is named for him.