Timothy Sullivan (1835 – October 6, 1910) was a Union Navy sailor in the American Civil War and a recipient of the U.S. military's highest decoration, the Medal of Honor. Born in 1835 in Ireland, Sullivan immigrated to the United States and was living in New York when he joined the U.S. Navy. He served during the Civil War as a coxswain on the USS Louisville. Acting as a gun captain during battle, Sullivan showed "attention to duty, bravery, and coolness" through various engagements. For these actions, he was awarded the Medal of Honor on April 3, 1863.