Elachista poae is a moth of the Elachistidae family. It is found from Fennoscandia and the Baltic region to Belgium, the Alps and Hungary and from Ireland to Romania. The wingspan is 9–12 mm. Adults are on wing from April to May and from June to August. The larvae feed on Glyceria maxima. They mine the leaves of their host plant. The mine has the form of a narrow gallery, descending from the leaf tip to within the sheath of the leaf. The frass is dispersed. Pupation takes place outside of the mine. Larvae can be found from April to May and again from July to August.