The current study aims to update the list and revise the nomenclature of Acacia s.l., the most widespread genus in Yemeni flora, both native and introduced. The study was compiled by consulting a number of information sources, including relevant literature and online databases. According to recent molecular phylogenetic studies, Acacia s.l. is polyphyletic and the recognition of seven genera is strongly supported. Hence the classical identity of Acacia needs to be changed. Consequently, the current position of various taxa present in Yemen, which was formerly placed in Acacia s.l., has been transferred to Acacia s.s. Vachellia and Senegalia. This has resulted in six species of Acacias, fifteen species with several subspecies and varieties in Vachellia and six species in Senegalia including six endemics, one near endemic and four regionally endemics. This has resulted in six species of Acacias, fifteen species with several subspecies and varieties in Vachellia and six species in Senegalia including six endemics, one near endemic and four regionally endemics.