List of participating nations at the Summer Olympic Games

This is a list of nations, as represented by National Olympic Committees (NOCs), that have participated in the Summer Olympic Games between 1896 and 2016. As of the 2016 Games, all of the current 206 NOCs have participated in at least one edition of the Olympic Games, and athletes from Australia (including two Games featuring the Australasia team), France,Great Britain, Greece and Switzerland have competed in all twenty-eight Summer Olympic Games. The United States has only missed the 1980 Summer Olympics due to a boycott lead by American president Jimmy Carter.

Early Games were not clearly documented with respect to participating nations. Competitors from 11 to 16 different nations participated in the inaugural 1896 Games, in Athens. Eleven nations (Australia, Austria, Denmark, England, France, Germany, Greece, Hungary, Sweden, Switzerland, and the United States) are mentioned in the official report for the Games, and the International Olympic Committee (IOC) states that 14 nations were represented. The NOCs for Bulgaria and Chile each claim that they were represented by a single athlete in Athens. Other sources also list Egypt, Italy, and the Turkish Empire.