Achlya flavicornis, the yellow horned, is a moth of the family Drepanidae. The species was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae. It is found from Europe to the eastern Palearctic ecozone. The final instar larva is either off white all over or off white below the spiracles and darker greyish or olive green dorsally. There is a row of black spots and finely black-edged white dots. The insect overwinters as a pupa in a cocoon, amongst leaf litter. The larvae feed on birch.