William Michael Heinen Jr. (born January 17, 1967) is an American professional golfer who has played on the PGA Tour and the Nationwide Tour.

He attended the University of Louisiana at Lafayette from 1985–1989, and was a two-time All-American member of the golf team.

In 1994, he won the Shell Houston Open in just his 10th start on the PGA Tour.

He lives in Lake Charles, Louisiana with his wife and three children.

PGA Tour playoff record (0–1) Buy.com Tour playoff record (0–2) Note: Heinen never played in The Open Championship.