A clay court is one of the four different types of tennis court. Clay courts are made of crushed shale, stone or brick. The red clay is slower than the green, or Har-Tru "American" clay. The French Open uses clay courts, making it unique among the Grand Slam titles.

Although more traditional and cheaper to construct than other types of tennis courts, maintenance costs are higher than those of hard courts. Clay courts need to be rolled to preserve flatness. The clay's water content must be balanced; green courts generally require the courts to be sloped to allow water run-off.http://www.xsports.com/clay.html

Clay courts are more common in Europe and South America than in the United States. In the U.S. courts made of green clay, also known as "rubico", are often called "clay," but are not made of the same clay used in most European and South American countries.