The Men's 400 metres T38 event at the 2012 Summer Paralympics took place at the London Olympic Stadium from 2 to 3 September.

T38 athletes have the mildest form of impairment caused by cerebral palsy, often in only one limb, and not affecting the ability to run, walk or jump freely, although impairing performance.

T38 athletes may suffer minor co-ordination difficulties.

Prior to the competition, the existing World and Paralympic records were as follows: Competed 2 September 2012 from 10:52.

rule: first 3 in each heat (Q) plus the 2 fastest other times (q) qualified.