In order to provide a basis for future studies on the functional morphology and evolutionary history of the New Zealand moas, the species-level systematics of the family is reviewed. Based on a study of museum collections and an analysis of intraspecific variability, only 13 species are considered to be valid: Anomalopteryx didiformis, A. oweni, Megalapteryx didinus, M. benhami, Pachyornis elephantopus, P. mappini, Euryapteryx curtus, E. geranoides, Emeus crassus, Dinornis struthoides, D. torosus, D. novaezealandiae, and D. giganteus. The taxa accepted as valid in this paper probably fit the biological species concept more closely than do those of previous classifications, in which as many as 29 species have been recognized. The “species-pairs,” Pachyornis mappini-P septentrionalis, Euryapteryx curtus-E. exilis, E. geranoides- E. gravis, and Emeus crassus-E. huttonii probably represent examples of sexual size dimorphism.