This study provides a multiproxy detailed analysis of the Eocene–Oligocene sedimentary succession exposed in northern Bahariya Depression (Western Desert, Egypt), integrating sedimentology, paleontology, and litho- and biofacies investigations. The Eocene rocks described in this area constitute, from base to top, the Naqb (early Eocene), Qazzun and El-Hamra formations (middle–late Eocene), which are unconformably overlain by the Oligocene rocks of the Radwan and El-Ris formations, respectively. Four benthic foraminiferal and five macrofuanal assemblages were identified from the Eocene succession and interpreted in terms of palaeoecology and palaeobiogeographic distributions. Field-based description supported by detailed petrographic investigations of the Eocene rocks enabled the discrimination of sixteen microfacies types that form four distinctive genetically-related facies associations deposited …