John Titus Mather (1854-1928) was an American businessman and philanthropist. He was born in Port Jefferson, New York, on June 27, 1854, and died in Habana, Cuba, on March 30, 1928. The descendant of a shipbuilding family, he spent most of his active life in that industry. The annals of shipbuilding in the Port Jefferson vicinity are closely related to John T. Mather and his blood predecessors.