William David McCain (March 29, 1907, in Bellefontaine, MS – September 5, 1993) was a racist and recognized leader of the Mississippi political establishment and a leader in its struggle in the 1950s and 1960s to maintain the "southern way of life" including racial segregationism.
He served as Mississippi state archivist, a Major General in the Mississippi National Guard, longtime leader and promoter of the Sons of Confederate Veterans, fifth president and major architect of Mississippi Southern College (now The University of Southern Mississippi).
McCain married the former Minnie Leicester Lenz on October 3, 1931, and they were parents of three children: William D., Jr., John W., and Patricia.