William Fred Mayfair (born August 6, 1966) is an American professional golfer who plays on the PGA Tour Champions.

He holds the distinction of being the only player to ever beat Tiger Woods in a playoff on the PGA Tour (1998 Nissan Open).

He finished 142nd on the Tour money list that year, which granted him conditional status for 2011.

During his PGA Tour career, Mayfair made 761 starts and earned over $20.3 million.

Mayfair lives in Scottsdale, Arizona, where he plays out of Estrella Mountain Ranch Golf Club.