John Mills Allen (July 8, 1846 – October 30, 1917) was a member of the United States House of Representatives from Mississippi.
Allen was born in Tishomingo County, Mississippi on July 8, 1846. He attended the common schools during the Civil War, enlisted as a private in the Confederate Army, and served throughout the war. Allen also attended Cumberland School of Law in Lebanon, Tennessee, and graduated from the law department of the University of Mississippi in 1870. Allen was admitted to the bar the same year and commenced practice in Tupelo, Mississippi.
Allen served as district attorney for the first judicial district of Mississippi from 1875 to 1879. He was elected as a Democrat to the Forty-ninth and to the seven succeeding Congresses (March 4, 1885 – March 3, 1901). Allen served as chairman of the Committee of Expenditures in the Department of Justice (Fifty-second Congress), and of the Committee on Levees and Improvements of the Mississippi River (Fifty-third Congress).
Allen declined to be a candidate for reelection in 1900 to the Fifty-seventh Congress and then he was appointed in March 1901 as United States commissioner to the St. Louis Exposition of 1904. Afterwards he resumed the practice of law in Tupelo, Mississippi, and died there October 30, 1917. He was interred in Glenwood Cemetery.