Racquetball is a sport played with racquets and a hollow rubber ball on an indoor or outdoor court. Unlike most racquet sports, usage of the walls, floor, and ceiling of the court is considered legal in the context of the sport, rather than out-of-bounds.

The sport was invented by Joe Sobek in 1948, incorporating rules from squash and handball. The game is normally played by two opposing players, though variations involving three and four players are also commonly played.

The basic rules of Racquetball, provided by La Mesa Racquetball.