Athletics at the 1912 Summer Olympics – Men's 400 metres
The men's 400 metres was a track and field athletics event held as part of the Athletics at the 1912 Summer Olympics programme. The competition was held on Friday, July 12, 1912, and on Saturday, July 13, 1912. Forty-nine runners from 16 nations competed. NOCs could enter up to 12 athletes. The event was won by Charles Reidpath of the United States, the nation's fourth title in the event. Hanns Braun of Germany took silver, the nation's first medal in the men's 400 metres.