This is a list of nations, as represented by National Olympic Committees (NOCs), that have participated in the Summer Olympic Games between 1896 and 2020 (held in 2021). As of the 2020 Games, all of the current 206 NOCs have participated in at least two editions of the Olympic Games. Athletes from Australia,a France,[K] Great Britain, Greece, Italy[R] and Switzerland[M] have competed in all twenty-nine Summer Olympic Games.