The 2008 Summer Olympics (Chinese: 2008年夏季奥运会), officially the Games of the XXIX Olympiad (Chinese: 第二十九届夏季奥林匹克运动会) and officially branded as Beijing 2008 (Chinese: 北京2008), were an international multisport event held from 8 to 24 August 2008, in Beijing, China. A total of 10,942 athletes from 204 National Olympic Committees (NOCs) competed in 28 sports and 302 events, one event more than those scheduled for the 2004 Summer Olympics. This was the first time China had hosted the Olympic Games, and the third time the Summer Olympic Games had been held in East Asia, following the 1964 Olympics in Tokyo, Japan, and the 1988 Olympics in Seoul, South Korea. These were also the second Summer Olympic Games to be held in a communist state, the first being the 1980 Summer Olympics in the Soviet Union (with venues in Russia, Ukraine, Byelorussia, and Estonia).

Beijing was awarded the 2008 Games over four competitors on 13 July 2001, having won a majority of votes from members of the International Olympic Committee (IOC) after two rounds of voting. The government of the People's Republic of China actively promoted the 2008 Games and invested heavily in new sports venues and transportation infrastructure. 37 venues were used to host the events, including twelve constructed specifically for the 2008 Games. The equestrian events were held in Hong Kong, making these the third Olympics for which the events were held under the jurisdiction of two different NOCs. The sailing events were contested in Qingdao, while the football events took place across several different cities.

The official logo for the 2008 Games, titled "Dancing Beijing" (舞动北京), created by Guo Chunning (郭春宁), featured the Chinese character for capital (京, stylized into the shape of a human being) in reference to the host city. The 2008 Olympics were watched by 3.5 billion people worldwide, and featured the longest distance for an Olympic Torch relay. The 2008 Games also set numerous world and Olympic records, and were the most expensive Summer Olympics of all time, and the second most expensive overall, after the 2014 Winter Games in Sochi. The opening ceremony was lauded by spectators and numerous international presses as spectacular, spellbinding, and by many accounts, "the greatest ever in the history of Olympics". Beijing hosted the 2022 Winter Olympics, making it the first city ever to host both the Summer and Winter Games.

An unprecedented 87 countries won at least one medal during the 2008 Games. Host nation China won the most gold medals (48), and became the seventh different team to top the Summer Olympics medal standings, winning a total of 100 medals overall. The United States placed second in the gold medal tally but won the highest number of medals overall (112). The third place in the gold and overall medal tally was achieved by Russia.

This Olympic Games marked the return of the Summer Olympic Games to Asia after the 1988 Olympics in South Korea. It was the first Olympics for Serbia as a separate state since 1912 and the first for Montenegro, having separated from Serbia in 2006. It was also the first Olympics for Nepal as a republic, the Marshall Islands and Tuvalu. Mongolia and Panama each won their first Olympic gold medal. In addition, Afghanistan, Mauritius, Serbia, Sudan, Tajikistan and Togo won their first Olympic medals at these Games. North Korea, having symbolically marched with South Korea as one team at the opening ceremonies of the preceding three Games that it entered (2000 in Sydney, 2004 in Athens, and 2006 in Turin), paraded separately this time.

Under the direction of Liu Qi, Beijing was elected as the host city for the 2008 Summer Olympics on 13 July 2001, during the 112th IOC Session in Moscow, defeating bids from Toronto, Paris, Istanbul, and Osaka. Prior to the session, five other cities (Bangkok, Cairo, Havana, Kuala Lumpur, and Seville) had submitted bids to the IOC, but failed to make the short list chosen by the IOC Executive Committee in 2000. After the first round of voting, Beijing held a significant lead over the other four candidates. Osaka received only six votes and was eliminated. In the second round, Beijing was supported by a majority of voters, eliminating the need for subsequent rounds. Toronto's bid was its fifth failure since 1960 (failed bids for 1960, 1964, 1976 and 1996 Games, losing to Rome, Tokyo, Montreal and Atlanta).

When bidding for the Games, Beijing actually proposed different dates (25 July - 10 August for the Games of the XXIX Olympiad and 27 August - 7 September for the XIII Paralympic Games).

Members of the IOC did not disclose their votes, but news reports speculated that broad international support led to China's selection, especially from developing nations that had received assistance from China to construct stadiums. The size of China, its increased enforcement of doping controls, and sympathy concerning its loss of the 2000 Summer Olympics to Sydney were all factors in the decision. Eight years earlier, Beijing had led every round of voting for the 2000 Summer Olympics before losing to Sydney by two votes in the final round.