John Clayton Allen (February 14, 1860 – January 12, 1939) was an American politician who represented Illinois in the United States House of Representatives from 1925 to 1933.

Allen moved to Monmouth, Illinois, in 1896 and became president of the John C. Allen Co. department store and of the People's National Bank of Monmouth.

He served as member of the State normal school board 1917-1927 and was elected as a Republican to the Sixty-ninth and to the three succeeding Congresses (March 4, 1925 – March 3, 1933).

After leaving Congress, he resumed his former business pursuits in Monmouth, Illinois until his death there in 1939.

This article incorporates public domain material from the Biographical Directory of the United States Congress