Diverse and well-preserved terrestrial palynomorphs occur in the Padeha, Khoshyeilagh, and Mobarak formations in the Khoshyeilagh area, northeastern Alborz, northern Iran. The spore assemblages consist of 36 species belonging to 24 genera. The vertical distribution of index spores allows the erection within these strata of five local biozones (BT, FF, LE, LN, and VI). The data show that assemblages recorded from the Khoshyeilagh section can be correlated with the VCo, LE, LN, and VI Miospore biozones of Europe, Canada, and USA. Many of the palynomorph species, such as Archaeoperisaccus ovalis, Ancyrospora ampulla, Diducites mucronatus, D. versabilis, Grandispora cornuta, G. echinata, Indotriradites explanatus, Retispora lepidophyta, Retusotriletes incohatus, R. phillipsii, Rugospora flexuosa, Teichertospora torquata, Tumulispora malevkensis, Vallatisporites pusillites, Verrucosisporites bulliferus, and Verrucosisporites nitidus, are closely comparable with coeval assemblages recorded from Belgium, Portugal, Canada, North Africa, South America, and North America. This indicates the close relationship of the Iranian Platform to other parts of the northern Gondwana and southern Laurentian domain during this time interval. Moreover, parent plants of the Late Devonian miospores in the Khoshyeilagh area generally belong to herbaceous Class Rhyniopsida (orders: Rhyniales, Trimerophytales), Zosterophyllopsida, and various classes such as, Lycopsida (herbaceous order: Isoetales, Selaginellales, Protolepidodendrales), Progymnospermopsida (Order Archaeopteridales and Aneuropthytales), and Filicopsida. The presence of marine shelly macrofauna (brachiopods and corals) suggest a nearshore depositional environment comprising rivers, fluvial deltas, tidal flats, and lagoons for the Upper Devonian and lowermost Carboniferous deposits studied herein.