Mythimna pallidicosta is a moth in the family Noctuidae first described by George Hampson in 1894.

It is found from north-eastern India to western China, Sri Lanka, Taiwan, Sundaland, Flores, the Philippines and Japan.

Vertex of head of the costa of forewing and veins of outer areas are whitish.

Male lack paired tufts on basal segments of abdomen below.

There are fairly prominent postmedial and marginal series of black specks.