Idiophantis acanthopa is a moth of the Gelechiidae family. It was described by Meyrick in 1931. It is found in India. The wingspan is 12-l4 mm. The forewings are light brownish. The discal stigmata are minute and black, the plical represented by some slight fuscous suffusion obliquely beyond the first discal. There is a curved white line edged dark fuscous from the costa at three-fourths to the tornus, immediately preceded by an ochreous line obscurely edged fuscous anteriorly. The costal edge beyond this is white and the apical projection ochreous including a white mark, the space between this and the line pale yellowish, with a small blackish spot beyond the line in the middle. The hindwings are pale silvery-grey.