General Duke (born 1865) was an American Thoroughbred racehorse who won the second running of the Belmont Stakes in 1868. A son of Lexington, he was bred by Robert A. Alexander in Kentucky. He raced as a two-year-old, winning twice, including a stakes race. As a three-year-old, he raced nine times, winning six races, including several stakes. His final racing record was 18 wins from 32 starts. He was later known as Judge Curtis, and after his racing career ended he was a breeding stallion in Canada before dying in Illinois in 1888. Three of his daughters won stakes races.