Australia has sent athletes to all editions of the modern Olympic Games. Australia has competed in every Summer Olympic Games, as well as every Winter Olympics except 1924–32 and 1948. In 1908 and 1912 Australia competed with New Zealand under the name Australasia.
Thailand first participated at the Olympic Games in 1952, and has sent athletes to compete in every Summer Olympic Games since then, except when they participated in the US-led boycott of the 1980 Summer Olympics. Thailand has also participated in the Winter Olympic Games since 2002.
The United States of America has sent many athletes to the celebration of the Olympic Games, starting with the first modern Olympics held in 1896. The United States has sent athletes to every Olympic Games with the exception of the 1980 Summer Olympics, during which it led a boycott in protest of the Soviet Union's invasion of Afghanistan. The United States Olympic & Paralympic Committee (USOPC) is the National Olympic Committee for the United States.
Hungary first participated at the Olympic Games at the inaugural 1896 Games, and has sent athletes to compete in most Summer Olympic Games and every Winter Olympic Games since then. The nation was not invited to the 1920 Games for its role in World War I, and was part of the Soviet-led boycott of the 1984 Summer Olympics.
The United Kingdom has been represented at every modern Olympic Games, and as of the 2020 Summer Olympics is third in the all-time Summer Olympic medal table by both number of gold medals won and overall number of medals. London has hosted the Summer Olympic Games three times: in 1908, 1948, and 2012.
Italy has sent athletes to most of the modern Olympic Games held since 1896, outside of not having "officially" participated in the 1904 Summer Olympics.
Cuba first participated at the Olympic Games in 1900, and has sent athletes to compete in 20 of 28 Summer Olympic Games overall.
Brazil first participated at the Olympic Games in 1920, after missing the previous five Summer editions. The country has sent athletes to compete in every Summer Olympic Games since then, except for the 1928 Games. As of 2020, Brazilian athletes have won a total of 150 medals in 18 different Summer sports.
Nigeria first participated in the Olympic Games in 1952, and has sent athletes to compete in every Summer Olympic Games since then, except for the boycotted 1976 Summer Olympics. The nation participated in the Winter Olympic Games in 2018, having qualified female athletes in bobsleigh and skeleton.
Originally having participated in Olympics as the delegation of the Republic of China (ROC) from 1924 Summer Olympics to 1976 Winter Olympics,China competed at the Olympic Games under the name of the People's Republic of China (PRC) for the first time in 1952 Summer Olympics held in Helsinki, Finland, although they only arrived in time during the last days to participate in a one event. That year, the International Olympic Committee (IOC) allowed both the PRC and ROC to compete with the name "China", although the latter withdrew in protest. Due to the dispute over the political status of the "two Chinas", the PRC started a period of isolationism, withdrawing from several international sporting bodies and the UN system until the mid-1970s, when the country participated for the first time in the Asian Games in 1974 and the World University Games in 1977. Returning to the IOC officially only in 1979, which gave it the right to send an official delegation, starting from the 1980 Winter Olympics in Lake Placid, United States. Their first appearance at the Summer Olympic Games after 1952 was the 1984 Summer Olympics in Los Angeles, United States. The People's Republic of China staged boycotts of the Games of the XVI Olympiad in Melbourne, Australia, Games of the XVII Olympiad in Rome, Italy, Games of the XVIII Olympiad in Tokyo, Japan, Games of the XIX Olympiad in Mexico City, Mexico, Games of the XX Olympiad in Munich, Germany, and Games of the XXI Olympiad in Montreal, Canada. China also boycott the Games of the XXII Olympiad in Moscow, USSR due to the American-led boycott and the ongoing Sino-Soviet split, together with the other countries.
Portugal first participated at the Olympic Games in 1912 and has since taken part in every edition of the Summer Olympic Games. Earlier that year, the Olympic Committee of Portugal was recognised by the International Olympic Committee as the Portuguese National Olympic Committee. In 1952, athletes representing Portugal competed for the first time at the Olympic Winter Games, and have only missed two editions since 1988.
Poland first participated at the Olympic Games in 1924, and has sent athletes to compete in every Summer Olympic Games since then, except for the 1984 Games, when they were part of the Soviet-led boycott of the 1984 Summer Olympics. Poland has also participated in every Winter Olympic Games.
Algeria first competed at the Olympic Games in 1964, and has participated in every Summer Olympic Games since then, except for the boycotted 1976 Summer Olympics. Algeria has also sent athletes to the Winter Olympic Games on three occasions. The National Olympic Committee for Algeria is the Comité Olympique Algérien, founded in 1963.
New Zealand first sent an independent team to the Olympics in 1920. Prior to this, at the 1908 and 1912 Summer Olympics, New Zealand and Australian athletes competed together in a combined Australasia team. New Zealand has also participated in most Winter Olympic Games since 1952, missing only the 1956 and 1964 Games.
Venezuela first participated at the Olympic Games in 1948, and has sent athletes to compete in every Summer Olympic Games since then. Venezuela has also participated in the Winter Olympic Games since 1998. The Venezuelan Olympic Committee (COV) was created in 1935.
Athletes from Iceland first participated at the Olympic Games in 1908.
Tanzania first participated at the Olympic Games in 1964, and has sent athletes to compete in every Summer Olympic Games except for the boycotted 1976 Games and has never participated in the Winter Olympic Games.
Australia has participated officially in every Paralympic Games since its inauguration in 1960 except for the 1976 Winter Paralympics.
Norway has participated in every edition of both the Summer and Winter Paralympics, except the second Summer Games in 1964. It was one of the seventeen countries to take part in the inaugural Paralympic Games in 1960 in Rome, where it sent a delegation of eleven athletes. Norway was the host country of both the 1980 Winter Paralympics, in Geilo, and the 1994 Winter Paralympics, in Lillehammer.
Kenya 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, they did not participate in the 1976 Summer Olympics in Montreal and the 1980 Summer Olympics in Moscow because of the African and United States boycott.
