John Baptiste Fournet (July 27, 1895 – June 3, 1984) was an American attorney and politician who served as Speaker of the Louisiana House of Representatives, lieutenant governor of Louisiana from 1932 to 1935, and a justice of the Louisiana Supreme Court, serving as an associate justice from 1935 to 1949, and as Chief Justice by seniority from 1949 to 1970.

Born in St. Martinville, Fournet attended Louisiana State Normal College, and was a teacher, and even principal at Morganza High School for a period before entering the law school of LSU in 1917.^[1] His studies were interrupted by service in World War I, after which he received an LL.B. from Louisiana State University in 1920.^[2][1]

A supporter of Huey P. Long, Fournet served in the Louisiana House of Representatives from 1928 to 1932, and as lieutenant governor of Louisiana from 1932 to 1935, when Fournet was elected to the Louisiana Supreme Court. Fournet was walking next to Long when the latter was assassinated later that year.^[2]

Fournet became chief justice of Louisiana by seniority in 1949, and remained on the court until 1970, when he reached the maximum age of service of 75.^[2]