The Summer Olympic Games or the Games of the Olympiad are an international multi-sport event, usually quadrennial, organised by the International Olympic Committee. Medals are awarded in each event, with gold medals for first place, silver for second and bronze for third, a tradition that started in 1904. The Winter Olympics were also created due to the success of the Summer Olympics.

The Games have expanded from a 42-event competition with fewer than 250 male athletes to a 300-event sporting tradition with over 10,000 competitors of both sexes from 205 nations. Organizers for the 2008 Summer Olympics in Beijing expected approximately 10,500 athletes to take part in the 302 events on the program for the Games. The 2004 Summer Olympics, for which organizers had also expected 10,500 competitors, drew a total of 11,099 in the 301 events offered.

Competitors are entered by a National Olympic Committee (NOC) to represent their country of citizenship. National anthems and flags accompany the medal ceremonies, and tables showing the number of medals won by each country are widely used. In general only recognized nations are represented, but a few sovereign-disputed countries are allowed to take part.

The United States has hosted four Summer Olympics games, more than any other nation. The United Kingdom will have hosted three Summer Olympics games (all in London) when they return to the British capital in 2012. Australia, France, Germany and Greece have all hosted the Summer Olympic Games twice. Other countries that have hosted the Summer Olympics are Belgium, Canada, Finland, Italy, Japan, Mexico, Netherlands, South Korea, Spain, the Soviet Union and Sweden. The People's Republic of China hosted the Summer Olympics for the first time in Beijing in 2008. Four cities have hosted two Summer Olympic Games: Los Angeles, London, Paris and Athens. Stockholm, Sweden, has hosted events at two Summer Olympic Games, having hosted the games in 1912 and the equestrian events at the 1956 Summer Olympics - which they are usually listed as jointly hosting. Events at the Summer Olympics have also been held in Hong Kong and The Netherlands (both represented by their own NOCs), with the equestrian events at the 2008 Summer Olympics being held in Hong Kong and two sailing races at the 1920 Summer Olympics being held in The Netherlands.

Five countries - Australia, France, Great Britain, Greece, and Switzerland - have been represented at all Summer Olympic Games. Greece is the only one to have participated under its own flag in all Games. The only country to have won at least one gold medal at every Summer Olympic Games is Great Britain, ranging from one gold in 1904, 1952 and 1996 to fifty-six golds in 1908.