Robert Gustave "Bun" Troy (August 27, 1888 – October 7, 1918) was a German-born professional baseball pitcher who was killed in action while fighting against German forces in World War I.
Troy was a sergeant with the "Blue Ridge" Division of the United States Army; he was shot in the chest during Meuse-Argonne Offensive.
Before serving in the military, Troy had played five seasons in minor league baseball from 1910 to 1914 and had consecutive 23-win seasons in 1912 and 1913.
He pitched one game in Major League Baseball, for the Detroit Tigers against the Washington Senators, on September 15, 1912.
Troy pitched six scoreless innings in a pitching duel with Walter Johnson before giving up four runs in the seventh inning.