The Men's 400 metres T12 event at the 2012 Summer Paralympics took place at the London Olympic Stadium from 2 to 6 September.

Athletes in this category will generally have some residual sight, the ability to recognise the shape of a hand at a distance of 2 metres and the ability to perceive clearly will be no more than 2/60.

Prior to the competition, the existing World and Paralympic records were as follows: Competed 2 September 2012 from 19:00.

rule: winner of each heat (Q) plus the 4 fastest other times (q) qualified.

rule: winner of each heat (Q) plus the two fastest other times (q) qualified.