Mark Willard Clark (born May 12, 1968) is a former right-handed pitcher in Major League Baseball. He pitched all or part of ten seasons in the majors.
Clark was born in Bath, Illinois, and made his debut on September 6, 1991 for the St. Louis Cardinals. Over the next nine seasons, Clark would develop into a journeyman starting pitcher, being traded from team to team. He pitched in one postseason game in the 1998 National League Division Series for the Chicago Cubs, a game which he lost to John Smoltz and the Atlanta Braves.
He was released by the Texas Rangers during the 2000 season, then retired. He and his wife Amy have two children: a boy named Brandon and a girl called Allyson. They now live in Kilbourne, Illinois. He is now a baseball coach for children in the Kilbourne area.