Michael Joseph Hornung (June 12, 1857 – October 30, 1931) was an American baseball player.

Prior to starting his career in Major League Baseball in 1879 with the Buffalo Bisons, Hornung played for the 1877 and 1878 London Tecumsehs in London, Ontario, Canada, winning the International Association title in 1877.

After umpiring for a few seasons in the minor leagues he took on the roll of player / manager for the Batavia Giants franchise on May 25, 1897, making his playing debut on June 14 at the age of 40, he went hitless.

He was remarkable for his nearly flawless play in left field[1] and also known for his peculiar habit of shouting "ubbo ubbo" whenever he got a hit or made a good fielding play.

[2] In addition to being an exceptional fielder, Hornung was also a fast baserunner, stealing 39 bases in his final season, and was a fair hitter, batting .302 in 1882.