Thomas Muster (born October 2, 1967 in Leibnitz, Austria) is a retired and former World No. 1 tennis player from Austria. He was one of the world's leading clay court players in the 1990s, and at his peak was known as "The King of Clay." He won the French Open in 1995.
Muster first came to prominence when he reached the final of the French Open junior tournament and the Orange Bowl juniors tournament in 1985. He turned professional later that year and won his first tour title at Hilversum, (Netherlands) in 1986.
In 1988, Muster reached six tour finals, winning four of them. He finished the year ranked in the world's top 20 for the first time.