The men's 400 metres sprint event at the 1936 Olympic Games took place in early August.

The final was won by 0.2 seconds by American Archie Williams, the third consecutive and seventh overall title in the event for the United States.

Archie Williams of the United States was the favorite, setting the world record at 46.1 seconds at the 1936 NCAA championships.

The United States made its tenth appearance in the event, the only nation to compete in it at every Olympic Games to that point.

The top three runners in each semifinal heat advanced, making a six-man final.