Finland competed at the 2012 Summer Olympics in London, from 27 July to 12 August 2012. The nation has competed at every Summer Olympic Games since its official debut in 1908. The Finnish Olympic Committee sent a total of 56 athletes to the Games, 29 men and 27 women, to compete in 14 sports. There was only a single competitor in artistic gymnastics, taekwondo, weightlifting and tennis.
Iran competed at the 2012 Summer Olympics in London, from 27 July to 12 August 2012. The nation has competed at every Summer Olympic games since its return in 1948, after having made their debut in 1900, with the exception of the 1980 and 1984 Summer Olympics. The National Olympic Committee of the Islamic Republic of Iran sent the nation's second-largest delegation to the Games, one less than it sent to Beijing. A total of 53 athletes, 45 men and 8 women, competed in 14 sports. This was also the youngest delegation in Iran's Olympic history, with half the team under the age of 25, and many of them are expected to reach their peak in time for the 2016 Summer Olympics in Rio de Janeiro. Heavyweight boxer Ali Mazaheri was the nation's flag bearer at the opening ceremony.
Latvia competed at the 2012 Summer Olympics in London, United Kingdom from July 27 to August 12, 2012. This was the nation's tenth appearance at the Summer Olympics.
Uzbekistan competed at the 2012 Summer Olympics in London, from July 27 to August 12, 2012. This was the nation's fifth consecutive appearance at the Olympics. The National Olympic Committee of the Republic of Uzbekistan sent the nation's smallest delegation to the Games in the post-Soviet era. A total of 54 athletes, 36 men and 18 women, competed in 13 sports. There was only a single competitor in fencing, rhythmic and trampoline gymnastics, shooting and tennis.
Hungary competed at the 2012 Summer Olympics in London, from 27 July to 12 August 2012. Hungarian athletes have competed at every Summer Olympic Games in the modern era, except the 1920 Summer Olympics in Antwerp, and the 1984 Summer Olympics in Los Angeles because of the Soviet boycott. The Hungarian Olympic Committee sent the nation's smallest delegation to the Games since 1956 to London. A total of 159 athletes, 97 men and 62 women, competed in 18 sports.
Bulgaria competed at the 2012 Summer Olympics in London, United Kingdom from 27 July to 12 August 2012. It was the nation's nineteenth appearance at the Summer Olympics, having missed the Olympics on three occasions, including the 1948 Summer Olympics in London due to the nation's role in World War II and 1984 Summer Olympics in Los Angeles because of the Soviet boycott. Despite this being London's third Olympic Games, this was the first time a Bulgarian team appeared at a London Olympics. The Bulgarian Olympic Committee sent the nation's smallest delegation to the Games, tying the record with Helsinki in 1952, and with Tokyo in 1964. A total of 63 athletes, 36 men and 27 women, competed in 16 sports. Men's volleyball was the only team event in which Bulgaria was represented in these Olympic games. There was only a single competitor in badminton, sprint canoeing, fencing, and judo.
Cuba competed at the 2012 Summer Olympics in London, from 27 July to 12 August 2012. This was the nation's nineteenth appearance in the Olympics. With baseball's removal from the Olympic program and the absence of the nation's volleyball team for the first time, the Cuban Olympic Committee sent the nation's smallest delegation to the Games since 1964. A total of 111 athletes, 66 men and 45 women, competed in 13 sports. There was only a single competitor in archery and table tennis.
Greece competed at the 2012 Summer Olympics in London, United Kingdom, from 27 July to 12 August 2012. The Hellenic Olympic Committee sent a total of 103 athletes to the Games in London, 65 men and 38 women, to compete in 19 sports. Men's water polo was the only team event in which Greece was represented at these Olympic Games.
Algeria competed at the 2012 Summer Olympics in London, United Kingdom, from 27 July to 12 August 2012. This was the nation's twelfth consecutive appearance at the Summer Olympics, except for the 1976 Summer Olympics in Montreal because of the African boycott.
Moldova competed at the 2012 Summer Olympics in London, from 27 July to 12 August 2012. This was the nation's fifth consecutive appearance at the Summer Olympics in the post-Soviet era.
Puerto Rico competed at the 2012 Summer Olympics in London, United Kingdom from July 27 to August 12, 2012. This was the nation's seventeenth consecutive appearance at the Olympics.
Nigeria competed at the 2012 Summer Olympics in London, from 27 July to 12 August 2012. This was the nation's fifteenth appearance at the Olympics. Nigeria missed the 1976 Summer Olympics in Montreal because of the African boycott. The Nigerian Olympic Committee sent the nation's smallest delegation to the Games since 1984. A total of 53 athletes, 30 men and 23 women, competed in 8 sports. Men's basketball was the only team-based sport in which Nigeria was represented at these Olympic Games. Among the eight sports played by the athletes, Nigeria marked its official Olympic debut in slalom canoeing.
Tajikistan competed at the 2012 Summer Olympics in London, from 27 July to 12 August 2012. This was the nation's fifth consecutive appearance at the Olympics. The National Olympic Committee of the Republic of Tajikistan sent the nation's largest delegation to the Games. A total of 16 athletes, 13 men and 3 women, competed in 7 sports. Six of these athletes had competed in Beijing, including judoka Rasul Boqiev and freestyle wrestler Yusup Abdusalomov, who both won Tajikistan's first ever Olympic medals.
Tunisia competed at the 2012 Summer Olympics in London, from 27 July to 12 August 2012. This was the nation's thirteenth appearance at the Olympics, having missed the 1980 Summer Olympics in Moscow because of its partial support for the United States boycott.
Senegal competed at the 2012 Summer Olympics in London, from 27 July to 12 August 2012. This was the nation's thirteenth appearance at the Olympics.
Cameroon competed at the 2012 Summer Olympics in London, United Kingdom, from 27 July to 12 August 2012. This was the nation's thirteenth appearance at the Olympics.
Venezuela competed at the 2012 Summer Olympics in London, from July 27 to August 12, 2012. This was the nation's seventeenth consecutive appearance at the Olympics, since its debut at the same host city in 1948. Celebrating the anniversary of the nation's Olympic debut, the British Embassy in Caracas invited former track cyclist Julio César León to travel back to the United Kingdom, and revisit his memories as the first Venezuelan athlete in history to compete at the games.
Mongolia competed at the 2016 Summer Olympics in Rio de Janeiro, Brazil, from 5 to 21 August 2016. Since the nation made its debut in 1964, Mongolian athletes had appeared in every edition of the Summer Olympic Games, with the exception of the 1984 Summer Olympics in Los Angeles, because of its partial support to the Soviet boycott.
Bahrain competed at the 2016 Summer Olympics in Rio de Janeiro, Brazil, from 5 to 21 August 2016. This nation marked its ninth consecutive appearance at the Summer Olympics.
Kyrgyzstan competed at the 2016 Summer Olympics in Rio de Janeiro, Brazil, from 5 to 21 August 2016. This was the nation's sixth consecutive appearance at the Olympics in the post-Soviet era.
Russian Empire (1900–1912)
Soviet Union (1952–1988)
Unified Team (1992)
