Justin Arch "Jay" Williamson IV (born February 7, 1967) is an American professional golfer who currently plays on the PGA Tour.

Williamson was born in St. Louis, Missouri. After graduating from Trinity College, he turned professional in 1990.

Williamson has no Tour victories, as he has had two runner-up finishes, one being the 2008 John Deere Classic, in which he lost to Kenny Perry in a one-hole playoff. He has amassed over one million dollars in career earnings.