John Nicholas Coyne Jr. (November 14, 1839 to March 4, 1907) was a United States military officer who fought with the Union Army as a member of the 70th New York Infantry during the American Civil War. He received his nation's highest award for valor, the U.S. Medal of Honor, for capturing an enemy flag while engaged in hand-to-hand combat during the Battle of Williamsburg in Virginia on May 5, 1862. That flag was "[t]he first Confederate flag captured on the battle-field" by the Union Army during the war, according to historian Thomas S. Townsend. Coyne's medal was conferred on April 18, 1888.