The identities of all the Lepidoptera described by C.P. Thunberg have been reviewed critically. Most Lepidoptera described by Thunberg came from Europe, but he also named several species from Asia (probably all from Ceylon and Japan), South Africa and the New World. Almost all Thunberg's specimens are still extant and the identity of most of the species he named can therefore be based on examination of authentic material. The results are presented in the form of an alphabetical catalogue of the species names proposed by Thunberg, with cross-references to Thunberg's publications and a complete listing of all specimens of species named by Thunberg in the Thunberg collection. Thunberg's collection, the authorship of the species described in his dissertations and the dates of Fabricius' Entomologia Systematica 3(2) and Thunberg's Fauna Svecica 7, both published in 1794, are discussed. Lectotypes are designated for most species and several new synonymies and new combinations are proposed. The identity of the two species named marginella Fabricius, 1781 is established (under fimthriella Thunberg). Lectotypes of Tinea marginella Fabricius, 1781 and Tinea sexpunctella Fabricius, 1794 are designated.