The men's 400 metres was an event at the 1980 Summer Olympics in Moscow. The competition was held from July 27 to July 30, 1980. Fifty athletes from 32 nations competed. The maximum number of athletes per nation had been set at 3 since the 1930 Olympic Congress. The event was won by Viktor Markin of the Soviet Union, the nation's first title in the men's 400 metres and first medal in the event since 1956. With the United States boycotting the Games, the country was not represented on the podium for the first time since 1920. Australia earned its first medal in the event with Rick Mitchell's silver, while East Germany won its first medal with Frank Schaffer's bronze, which was the first medal by any German since the United Team took silvers in 1956 and 1960.