Jack D. Rule Jr. (born November 13, 1938) is an American professional golfer who played on the PGA Tour in the 1960s.

Junior Amateur semi-finals but lost to Harlan Stevenson in the finals.

He graduated from the University of Iowa and turned professional in 1961.

[2] Rule played sparingly on the Champions Tour from 1989 to 2001, mostly in the U.S. Senior Open.

In 1993, Rule was inducted into the Iowa Golf Hall of Fame.