Royall Tyler (May 4, 1884 – March 2, 1953), was an American historian, who was a descendant of the American jurist and playwright Royall Tyler. He was born in Quincy, Massachusetts, and educated at Harrow School in England. After a time at New College, Oxford, he moved to the University of Salamanca, where he became a friend of Miguel de Unamuno. In 1909 he published Spain, a Study of her Life and Arts, the first work in English to recognize the genius of El Greco. Appointed by the British government to edit the Calendar of State Papers related to negotiations between England and Spain in the time of Charles V, Holy Roman Emperor, he published the first of the five volumes of these papers in 1913; the last, completed just before his death, appeared in 1954.