The women's 400 metres was the second-longest of the four women's track races in the Athletics at the 1964 Summer Olympics program in Tokyo.

23 athletes from 17 nations entered.

The 1964 Summer Olympics were the first to feature the women's 400 metres.

[1] The top five runners in each of the 3 heats advanced, as well as the next fastest runner from across the heats.

The fastest four runners in each of the two semifinals advanced to the final.