John Little McClellan (February 25, 1896 – November 28, 1977) was an American lawyer and politician. A member of the Democratic Party, he served as a U.S. Representative (1935–1939) and a U.S. Senator (1943–1977) from Arkansas. At the time of his death, he was the second most senior member of the Senate and chairman of the Senate Appropriations Committee. He is the longest-serving Senator in Arkansas history.