The men's 400 metres T13 event at the 2020 Summer Paralympics in Tokyo, took place between 1 and 2 September 2021.

The T13 category is for athletes with a moderate visual impairment.

Athletes in this category have a variety of visual impairments, but can typically recognize contours from a distance of 2 to 6 metres.

Athletes in this category do not typically require a guide.

Prior to the competition, the existing records were as follows:[1] Heat 1 took place on 1 September 2021, at 20:19:[2] Heat 2 took place on 1 September 2021, at 20:27:[3] The final took place on 2 September 2021, at 9:54:[4]