John Caleb Diez, Sr., known as Juba Diez (born August 18, 1944), is a businessman from Gonzales in Ascension Parish, south of Baton Rouge, Louisiana, who served in the Louisiana House of Representatives from 1976 to 2004.
He was first elected as a Democrat in 1975 in the state's first-ever nonpartisan blanket primary.
He won re-election in 1979, 1983, 1987, 1991, 1995, and 1999.