William Samuel Horton (November 16, 1865, Grand Rapids, Michigan, United States – October 1, 1936, Paris, France) was an American impressionist painter who mostly painted landscapes and water scenes. He spent a large part of his life in Europe, mostly in France and England, where he trained and developed his impressionist style with major impressionist artists. He is considered by art critics, gallerists and museums to be one of the major members of American impressionism, following on painters such as Mary Cassatt and Childe Hassam, but with a production mostly centered on European motives.