Athletics at the 2016 Summer Olympics – Men's 400 metres
The men's 400 metres event at the 2016 Summer Olympics took place between 12 and 14 August at the Olympic Stadium. Fifty-three athletes from 35 nations competed. The event was won by Wayde van Niekerk of South Africa, the nation's second gold medal in the men's 400 metres (after Bevil Rudd in 1920). Kirani James of Grenada and LaShawn Merritt of the United States became the sixth and seventh men to win two medals in the event, but Michael Johnson remained the only man with two gold medals.