
Argentina competed at the 1920 Summer Olympics in Antwerp, Belgium. It was the first time that the nation sent a team to compete at the Olympic Games, after individual Argentinian athletes had competed at the 1900 and 1908 Games.

Australia competed at the 1920 Summer Olympics in Antwerp, Belgium. Australian athletes have competed in every Summer Olympic Games.

Belgium was the host nation for the 1920 Summer Olympics in Antwerp. 336 competitors, 326 men and 10 women, took part in 121 events in 23 sports.

Brazil competed at the modern Olympic Games for the first time at the 1920 Summer Olympics in Antwerp, Belgium. 19 competitors, all men, took part in 10 events in 5 sports.

Canada competed at the 1920 Summer Olympics in Antwerp, Belgium. 52 competitors, all men, took part in 39 events in 9 sports. These games marked the introduction of winter sports to the Olympic program ; Canada won its first gold medal for ice hockey.

Chile competed at the 1920 Summer Olympics in Antwerp, Belgium.

Czechoslovakia competed at the 1920 Summer Olympics in Antwerp, Belgium. It was the first time that the nation had competed at the Summer Olympic Games, after the republic was founded in 1918. Previously, Bohemia had competed at the Olympic Games from 1900 to 1912.

Denmark competed at the 1920 Summer Olympics in Antwerp, Belgium. 154 competitors, 150 men and 4 women, took part in 66 events in 14 sports.

Egypt competed at the 1920 Summer Olympics in Antwerp, Belgium.

Estonia competed as a nation for the first time at the Summer Olympic Games at the 1920 Summer Olympics in Antwerp, Belgium. Estonia sent 14 athletes and 4 representatives to those games. Representatives were Ado Anderkopp, Leopold Tõnson, William Fiskar and Karl Metti.

Finland competed at the 1920 Summer Olympics in Antwerp, Belgium for the first time as a fully independent state. It did compete at the previous Olympics, however, only as the Russian-dependent Grand Duchy of Finland. 63 competitors, 62 men and 1 woman, took part in 51 events in 9 sports.

France competed at the 1920 Summer Olympics in Antwerp, Belgium. 304 competitors, 296 men and 8 women, took part in 113 events in 23 sports.

Great Britain, represented by the British Olympic Association (BOA), competed at the 1920 Summer Olympics in Antwerp, Belgium. 234 competitors, 218 men and 16 women, took part in 84 events in 21 sports. British athletes won fifteen gold medals and 43 medals overall, finishing third.

Greece competed at the 1920 Summer Olympics in Antwerp, Belgium. 47 competitors, all men, took part in 34 events in 8 sports. Greek athletes have competed in every Summer Olympic Games.

India sent its first Olympic team to the 1920 Summer Olympics in Antwerp, Belgium, some twenty years after a single athlete competed for India in 1900.

Italy competed at the 1920 Summer Olympics in Antwerp, Belgium. 174 competitors, 173 men and 1 woman, took part in 79 events in 18 sports.

The Empire of Japan competed at the 1920 Summer Olympics in Antwerp, Belgium.

Luxembourg competed at the 1920 Summer Olympics in Antwerp, Belgium.

Monaco competed in the Summer Olympic Games for the first time at the 1920 Summer Olympics held in Antwerp, Belgium.

The Netherlands competed at the 1920 Summer Olympics in Antwerp, Belgium. 130 competitors, 129 men and 1 woman, took part in 58 events in 15 sports.

New Zealand competed at the 1920 Summer Olympics in Antwerp, Belgium. It was the first time that the nation had competed independently at the Olympic Games. At the 1908 and 1912 Summer Olympics, New Zealand had competed with Australia in a combined team called Australasia.

Norway competed at the 1920 Summer Olympics in Antwerp, Belgium. 194 competitors, 188 men and 6 women, took part in 72 events in 16 sports.

Portugal competed at the 1920 Summer Olympics in Antwerp, Belgium. A delegation of thirteen competitors participated in two sports, however no medals were won.

The Union of South Africa competed at the 1920 Summer Olympics in Antwerp, Belgium. 39 competitors, 38 men and 1 woman, took part in 34 events in 7 sports.

Spain competed at the 1920 Summer Olympics in Antwerp, Belgium. It was only the second appearance of the nation at the Summer Games, after competing in the 1900 Summer Olympics, but missing the Games in 1904, 1908, and 1912. 58 competitors, all men, took part in 29 events in 7 sports.

Sweden competed at the 1920 Summer Olympics in Antwerp, Belgium. 260 competitors, 247 men and 13 women, took part in 100 events in 18 sports.

Switzerland competed at the 1920 Summer Olympics in Antwerp, Belgium. 77 competitors, all men, took part in 45 events in 13 sports.

The United States competed at the 1920 Summer Olympics in Antwerp, Belgium. 288 competitors, 274 men and 14 women, took part in 113 events in 18 sports.

Athletes from the Kingdom of Serbs, Croats and Slovenes competed at the 1920 Summer Olympics in Antwerp. Yugoslavia debuted at the Olympic Games participating in every edition of the Summer Olympics ever since. Eleven Yugoslav athletes participated in Belgium: only the football team – without the substitutes.