Mark Willard Clark (born May 12, 1968) is a former right-handed pitcher in Major League Baseball.

Clark was born in Bath, Illinois, and made his debut on September 6, 1991 for the St. Louis Cardinals.

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 and his wife Amy have two children: a son, Brandon and a daughter, Allyson.

This biographical article relating to an American baseball pitcher born in the 1960s is a stub.