Prophantis triplagalis is a moth in the family Crambidae.

It is found in India, where it has been recorded from the Khasia Hills.

The forewings are shining purplish grey, but the costa and a line of marginal dots are yellow.

There is a square, pale yellow, dark-edged spot in the middle of the cell and a larger irregularly reniform pale yellow blotch from the costa beyond the cell, with a darker dentate outer edge and a faint yellowish spot or two obliquely below it towards the base.

This Spilomelinae-related article is a stub.