Promacrochilo is a genus of moths of the Crambidae family. It contains only one species, Promacrochilo ambiguellus, which is found in China (Hainan), India, Nepal, Myanmar, Thailand and Malaysia. The forewings are yellow, with yellowish brown scales suffused along the veins and three dark brown spots at the middle of the cell. There is a series of dark brown spots from the costa to the middle of the inner margin. There is a blurry postmedial line on the hindwings from the costa to the inner margin.