The adult stage of Helioandesia tarregai gen. et sp. nov. (Lepidoptera: Yponomeutoidea: Heliodinidae) is described and illustrated from the arid western slopes of the Andes of northern Chile. The larvae of H. tarregai gen. et sp. nov. feed as leaf skeletonizers on Mirabilis acuta (Reiche) Heimerl (Nyctaginaceae). The mostly gray forewing of H. tarregai gen. et sp. nov., ornamented with strongly bulging metallic spots, resembles that of the representatives of the mainly Nearctic Lithariapteryx Chambers, 1876. However, the latter lacks CuP in the forewing, has a single bristle in the female frenulum, and lacks a well-developed cornutus. Helioandesia gen. nov. clustered as sister to Neoheliodines Hsu, 2004 in a cladistic analysis, although no synapomorphies were found for this cluster, while Lithariapteryx was sister to Helioandesia gen. nov. + Neoheliodines based on two synapomorphies. The genetic distance between a DNA barcode sequence of H. tarregai gen. et sp. nov. and representatives of other genera of Heliodinidae Heinemann, 1877 was 9.0–12.5% (K2P), and a maximum likelihood analysis based on this molecular marker confi rmed the placement of H. tarregai gen. et sp. nov. as a member of this micromoth family. This contribution represents the first confi rmed record of Heliodinidae for Chile.