The species of Adialytus Förster in Iran are taxonomically studied and new data on distribution and host associations are presented. The existence of a species complex, in the case of A. ambiguus (Haliday), and the morphological variability in commonly used taxonomic characters has been discussed. In total, four valid species belonging to the genus Adialytus including A. ambiguus (Haliday), A. salicaphis (Fitch), A. thelaxis (Starý) and A. veronicaecola (Starý) have been identified and recorded from Iran. Also, we recognized two additional phenotypes: “A. arvicola” (Starý) and “Adialytus cf. ambiguus” (Haliday). These phenotypes and A. veronicaecola are newly recorded from Iran in association with Sipha and Aphis species, respectively. An illustrated key for identification of the species and two variable phenotypes is presented.