A contribution to the taxonomy of the genus Phyllonorycter Hübner (Lepidoptera, Gracillariidae) is proposed, based on the morphological study of species developing on Ulmaceae. Species trophically associated with Ulmaceae belong to two subgenera: Phyllonorycter s. str. and a new subgenus, Juxtafera Baryshnikova, subgen. n. (type species Tinea tristrigella Hw.), both representing complex taxa. Three species-groups including species feeding on Ulmaceae as well as morphologically similar species developing on Betulaceae, Fabaceae, Salicaceae, Juglandaceae, and Rosaceae are established within the nominotypical subgenus; several species are characterized by disjunct oligophagy, consuming Ulmaceae together with plants of other families. Juxtafera subgen. n., established on the basis of the development of juxta in the male genitalia, is divided into 6 species-groups whose representatives are mainly strict oligophages, being predominantly associated with plants of three unrelated families Ulmaceae, Rosaceae, and Caprifoliaceae. Based on the comparative morphology of the male genitalia, evolutionary trends in Juxtafera are hypothesized.