Ice hockey tournaments have been staged at the Olympic Games since 1920. The men's tournament was introduced at the 1920 Summer Olympics and was transferred permanently to the Winter Olympic Games program in 1924, in France. The women's tournament was first held at the 1998 Winter Olympics. The Olympic Games were originally intended for amateur athletes until 1988, and the National Hockey League (NHL) did not allow its players to compete until 1998. From 1924 to 1988, the tournament started with a round-robin series of games and ended with the medal round. Medals were awarded based on points accumulated during that round. The games of the tournament follow the rules of the International Ice Hockey Federation (IIHF), which differ slightly from the rules used in the NHL.
In the men's tournament, Canada was the most successful team of the first three decades, winning six of seven gold medals. Czechoslovakia, Sweden and the United States were also competitive during this period and won multiple medals. Between 1920 and 1968, the Olympic hockey tournament was also counted as the Ice Hockey World Championship for that year. The Soviet Union first participated in 1956, and until 1992 they overtook Canada as the dominant international team, winning six of the ten tournaments in which they participated. Czechoslovakia won gold medals in 1956, 1976 and 1998. The United States won gold medals in 1960 and in 1980, which included their "Miracle on Ice" upset of the Soviet Union. Canada went 50 years without a gold medal, before winning one in 2002, and following it in 2010. Other nations to win gold include Great Britain in 1936 and Sweden in 1994 and 2006. Other medal-winning nations include Switzerland, Germany and Finland.
In 1986, the International Olympic Committee (IOC) voted to allow all athletes to compete in Olympic Games starting in 1988. The NHL was initially reluctant to allow its players to compete because the Olympics are held in the middle of the NHL season, and the league would have to halt play if many of its players participated. However, NHL players were allowed to compete starting in 1994. In 1998 and 2002, the format of the tournament was adjusted to accommodate the NHL schedule; a preliminary round was played without NHL players or the top six teams — Canada, Czechoslovakia, Finland, the Soviet Union, Sweden and the United States — followed by a final round which included them. The tournament format was changed again in 2006; every team played five preliminary games with the full use of NHL players.
In July 1992, the IOC voted to approve women's hockey as an Olympic event; it was first held at the 1998 Winter Olympics in Nagano. The Nagano Organizing Committee was hesitant to include the event because of the additional costs of staging the tournament, but an agreement was reached that limited the field to six teams, and ensured that no additional facilities would be built. The Canadian and American teams have dominated the event, typically losing only to each other. The United States won the first tournament in 1998, while Canada won in 2002, 2006, 2010 and 2014.