Robert McNutt McElroy (December 28, 1872 in Perryville, Kentucky - January 15, 1959 in Līhu'e, Hawaii) was a professor of history at Princeton University. He became a jingoistic advocate of a strong national defense during World War I, working with the Republican Party and the National Security League (NSL). A popular historian in his day, he published biographies of Grover Cleveland and Jefferson Davis, and respected histories of the states of Kentucky and Texas and the conquest of the American West, none of which are much cited today.