Softball began in 1887 when George Hancock, a reporter for the Chicago Board of Trade, invented "indoor baseball". By the spring of 1888, the game had spread outdoors. It was originally called either mushball, kittenball or indoor baseball, but by the 1920s it had acquired the name of softball. The sport became organised in the United States in 1933 with the formation of the Amateur Softball Association of America (ASA). The sport was originally played by men and did not become popular with women until the formation of the ASA.

Softball spread slowly to the rest of the world with, perhaps, it biggest push coming from American servicemen playing and teaching the game on the far-flung fields of World War II. It was not until 1965 that the International Softball Federation (ISF) was formed. Author Karen Christensen, in Encyclopedia of World Sport, notes that softball spread to the United Kingdom because of an American movie. The movie, "A Touch of Class", was filmed in London and featured a softball game, which began to be played in England as a result.

Softball consists of several disciplines: fast pitch, slow pitch, and modified fast pitch. Fast pitch allows two main underhand pitching deliveries; one that involves an entire revolution and the other where the pitchers arm comes back and then forward. Slow pitch requires the pitcher to lob the ball underhanded with an arc that reaches a minimum height of 1.83 metres and a maximum height of 3.66 metres. A modified fast pitch allows underhand deliveries but the arm must not make a complete revolution around the shoulder socket. Internationally, fast pitch is the dominant game. In the United States, slow pitch is played by millions of people in recreational leagues.

World championships in fast pitch softball were first held in 1965 for women and 1966 for men. Slow-pitch world championships began in 1987, and the competition resumed in Florida (USA) in June of 2002. The first world competition for junior men and women was held in 1981 and a World Cup for age 16-under girls began in 2001.