Genul Rattus este parte a subfamiliei gigante Murinae. În această subfamilie există alte câteva genuri, care sunt uneori considerate ca făcând parte din genul Rattus. Acestea sunt: Lenothrix, Anonymomys, Sundamys, Kadarsanomys, Diplothrix, Margaretamys, Lenomys, Komodomys, Palawanomys, Bunomys, Nesoromys, Stenomys, Taeromys, Paruromys, Abditomys, Tryphomys, Limnomys, Tarsomys, Bullimus, Apomys, Millardia, Srilankamys, Niviventer, Maxomys, Leopoldamys, Berylmys, Mastomys, Myomys, Praomys, Hylomyscus, Heimyscus, Stochomys, Dephomys și Aethomys.
Genul Rattus conține 64 de specii. S-a propus o nouă împărțire a speciilor din acest gen, dar aceasta nu cuprinde toate speciile incluse. Aceste grupuri sunt:
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