Idiophantis thiopeda is a moth of the Gelechiidae family. It was described by Meyrick in 1931. It is found in New Guinea.
The wingspan is about 17 mm. The forewings are pale yellow with a fuscous basal patch occupying nearly one-third of the wing, the edge convex. There is an oblique wedge-shaped mark formed of a pale greyish-ochreous streak between two dark fuscous streaks from the costa about two-thirds to the angle of a metallic-lilac-fuscous fasciate blotch occupying the termen from beneath the apex to the tornus, pointed beneath, its upper posterior angle blackish-fuscous. The apical projection including a white longitudinal streak, is limited anteriorly by a line of rather inwards-oblique fuscous strigula to the terminal blotch. The hindwings are light grey.