The Nygmiini is a tussock moth tribe which is redominantly distributed in most regions of the Old World. It was established in order to accommodate several genera that were previously associated with the polyphyletic genus Euproctis Hübner, 1819, which was erected upon the western European Euproctis chrysorrhoea (Linnaeus, 1758)(=Phalaena chrysorrhoea) and has included 682 valid specific names since the early 19th century. The caterpillars of Nygmiini are fairly polyphagous on various woody plant families, and thus many of them are considered as pests with significant importance. They are also known for having importance in public health due to the strong allergic reaction caused by the urticating setae. Although the tribe Nygmiini as well as the core genus Euproctis has such importance in various aspects, it¡¦s monophyletic status and phylogenetic relationships have never been tested using modern phylogenetic methods. I therefore sampled 175 lymantriid species representing most of the potential members of Nygmiini plus one arctiid species as the outgroup taxon to reconstruct the phylogeny of this tribe based on morphological characters from all development stages. The results suggest that the tribe Orgyiini forms a monophyletic clade with the Nygmiini, while neither the Nygmiini sensu Holloway nor the genus Euproctis sensu auctorum is monophyletic, and thus the taxonomic boundary of the tribe should be redefined in accordance to the hypothesis proposed by the present study. On the other hand, larval characters become the major source of the synapomorphies of the Nygmiini. The adult wing patterns which are used to taxonomic identification, however, are highly convergent among genera and thus these characters are not supposed to be informative in systematic research.