Athletics at the 2011 All-Africa Games – Men's 400 metres

The men's 400 metres event at the Athletics at the 2011 All-Africa Games was held on 11–13 September.

Qualification: First 3 of each heat (Q) and the next 6 fastest (q) qualified for the semifinals.

Qualification: First 3 of each semifinal (Q) and the next 2 fastest (q) qualified for the final.