Thiotricha niphastis 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 Western Australia. The wingspan is about 11 mm. The forewings are shining whitish, sprinkled with fuscous and a triangular fuscous spot on the base of the costa. The anterior half of the dorsum suffused with pale grey. There is an irregular fuscous spot in the disc at one-fourth, one beneath the middle of the disc, one on tornus, and one on costa at two-thirds. There is some irregular fuscous marking towards the apex and a blackish apical dot. The hindwings are light grey.