John Van Patter McDuffie (May 16, 1841 – November 18, 1896) was a U.S. Representative from Alabama. Born in Addison, New York, McDuffie attended the common schools. He moved with his parents to Bureau County, Illinois, in 1855. He attended Luther College (Iowa).In July 1861, he enlisted in Company B, 2nd Iowa Cavalry and served through the American Civil War. He became a sergeant major.He settled in Lowndes County, Alabama, and became a planter. He studied law and was admitted to the bar and commenced practice in Hayneville, Alabama.