William Francis Zinser (January 6, 1920 – March 16, 2001) was an American professional baseball pitcher.

He appeared two Major League Baseball games for the Washington Senators in 1944.

Zinser had a very short major league career, lasting only two games in 1944.

He is most known for scouting future Hall of Famer Sandy Koufax while he pitched for the University of Cincinnati in 1954.

This biographical article relating to an American baseball pitcher born in the 1910s is a stub.