Merimnetria lanaiensis is a moth of the Gelechiidae family. It is endemic to Lanai, Hawaii. The wingspan is about 11 mm. The forewings are ashy whitish, sparsely sprinkled with pale brownish fuscous, a small dark fuscous spot at the base of the costa is succeeded by a triangular fuscous costal patch, scarcely before the middle, and a few fuscous scales about the commencement of the costal cilia. The hindwings are ashy gray.