The alveolinid taxa, found in three stratigraphic sections of Eocene shallow-marine successions in the western Alborz (Baghdareh and Gheynarjeh sections) and eastern Iran (Chenesht section) regions, have been studied to determine their systematics and biostratigraphy for the first time. The rich alveolinid assemblages in these regions are correlated with coeval faunas (in shallow benthic zones) of the Tethyan province. The 29 species of alveolinids identified include: Glomalveolina lepidula, Alveolina ellipsoidalis, A. moussoulensis, A. subpyrenaica, A. aff. sakaraensis, A. tumida, A. decipiens, A. pisiformis, A. aragonensis, A. laxa, A. ilerdensis, A. rotundata, A. gr. guidonis, A. elliptica nuttalli, A. citrea, A. cf. citrea, A. cf. rugosa, A. cf. distefanoi, A. cf. montanarii, A. cremae, A. gr. cremae, A. cf. minuta, A. canavarii, A. oblonga, A. decastroi, A. aff. haymanensis, A. bayburtensis, A. frumentiformis, and A. aff. palermitana. On the basis of their distribution ranges, five Tethyan foraminiferal biozones have been recorded from the middle Ilerdian and Cuisian (SBZ7–8 and SBZ10–12) sedimentary successions. The data imply a close affinity between the studied area and other localities in the western Tethyan province.