Trichomyia is a cosmopolitan genus, and it is the only genus of Trichomyiinae to include extant species. In recent years, an increasing number of species belonging to the genus have been described, particularly from the Neotropics. However, phylogenetic studies of these species are lacking. In addition, few studies have focused on this group, and none has focused on it exclusively, making it difficult to classify objectively the high diversity known today. Herein, we present the first phylogenetic analysis of Trichomyia. We studied specimens from all continents to propose a phylogeny and used it as the basis of a new classification. Two clades proposed as genera were recovered. The canonical informal classification of Trichomyia into Groups A and B is discussed, and Gondwanotrichomyia is assigned a new status. Although we do not propose a subgeneric classification for Trichomyiinae, we provide some comments on the previously proposed subgenera based on our phylogeny. In addition, we report on the expanded distribution of Trichomyia festiva, Trichomyia gabia and Trichomyia imarui.