This book investigates archaisms and innovations in Tocharian nominal morphology: it provides a comprehensive treatment of the morphology of Tocharian grammatical gender, describing how it historically derived from the Indo-European proto-language and why it typologically deviates from most of the other Indo-European languages. The approach is both synchronic and diachronic, with a heavier focus on diachrony. The volume features a thorough study of a large number of nominal classes and pronominal forms, which are analysed from a derivational and an inflectional point of view in order to clarify their origin and development from the perspective of Indo-European comparative reconstruction. With its wide coverage of intricate phonological and morphological patterns, The Tocharian Gender System is an important contribution to the study of Tocharian nominal morphology as a whole.