William James Spiers III (born June 5, 1966) is an American college football coach who is the Special Teams Coordinator for Clemson.

He also played Major League Baseball as a shortstop and third baseman from 1989 to 2001 with the Milwaukee Brewers, 1989-1994, the New York Mets, 1995 and the Houston Astros, 1996-2001.

Spiers was a punter for Clemson University. He was a first round draft pick (13th overall) in the 1987 amateur draft. He debuted in the majors two years later with the Milwaukee Brewers on April 7, 1989. For his baseball career, he is known for his walk off single against Trevor Hoffman and the Padres in game 2 of the 1998 NLDS.

On September 24, 1999, while playing with the Houston Astros, Spiers was attacked by a 23-year-old man while standing in the outfield before the bottom of the 6th inning. Teammate Mike Hampton was first on the scene and delivered several kicks to the attacker. He was later quoted saying "The good thing was he didn't have a weapon... I always check right field before I deliver the first pitch. It's just a habit. I looked out there and saw the guy on Billy's back... It was a scary thing. My instincts just took over. My rage took over. I was pretty furious. I wanted to get him off my teammate." After being arrested the attacker faced two counts of battery and one count of disorderly conduct.^[1] Spiers wound up with a welt under his left eye, a bloody nose and whiplash.^[2]

As of 2016, Spiers is an offensive assistant at Clemson University Football, where he is also pursuing his graduate degree. In 2020, Spiers was Clemson Football Senior Assistant, Offense & Special Teams.^{[citation needed]}

On May 21, 2007 Spiers was inducted into the South Carolina Athletics Hall of Fame.^[3]

His son, Will, was a punter for the Clemson football team.^{[citation needed]} His nephew, Carson, is also a baseball player in the Cincinnati Reds organization. ^[4]