Prionopaltis subdentalis is a moth in the family Crambidae. It was described by Charles Swinhoe in 1894. It is found in Meghalaya, India.
The wings are uniform greyish olive, with a brown mark at the end of each cell. The forewings have a small brown spot within the cell. The exterior line starts with two white lunular marks at the costa. It is continued across the hindwings. The marginal points are black.