Thiotricha parthenica is a moth of the Gelechiidae family. It was described by Meyrick in 1904. It is found in Australia, where it has been recorded from New South Wales and Tasmania. The wingspan is 13–14 mm. The forewings are rather deep ochreous-yellow with the costal edge dark fuscous towards the base and with a minute black dot beneath the costa at one-third, and the stigmata minute and black, the plical obliquely before the first discal, but all these apparently sometimes absent. The hindwings are light grey.