John Julian McKeithen (May 28, 1918 – June 4, 1999) was a Governor of Louisiana.

He was a member of Louisiana state house of representatives between 1949 and 1952. He was a candidate for Lieutenant Governor of Louisiana in 1952. He served as governor between 1964 and 1972. He was an Independent candidate for U.S. Senator from Louisiana in 1972. His son, W. Fox McKeithen has served as Louisiana Secretary of State since 1988.