Dichomeris dicausta is a moth in the Gelechiidae family. It was described by Meyrick in 1913. It is found in India (Assam). The wingspan is 19–21 mm. The forewings are slaty-fuscous with a narrow fulvous-brown streak along the costa from the middle to near the apex, its costal edge dark fuscous. There are irregular narrow fulvous-brown streaks above and below the middle from near the base to two-fifths. The plical and second discal stigmata are represented by a few green-whitish scales, the latter preceded by a short obscure oblique longitudinal streak of fulvous brown suffusion. The hindwings are dark fuscous.