Arthur Kingsley Porter (1883-1933) was an American art historian specializing in medieval art and architecture. He was educated at Yale University and Columbia University. He taught at Yale and later became a professor of fine arts at Harvard University. He was a pioneer in the study of medieval art in the United States, known for his work on Romanesque sculpture and architecture in France and Spain. He disappeared at sea near Inishbofin, Ireland, in 1933.