Zooarchaeology of Ancient Greek Sanctuaries in Southwestern Sicily addresses the topic of ancient Greek sacrificial practices that were performed in the western colonies of Sicily between the 7th and 3rd centuries BC. The approach is primarily centered on zooarchaeology, focusing on the analysis of faunal assemblages derived from three crucial sacred areas associated with the outstanding poleis of Selinus and Akragas. Adopting a comprehensive interdisciplinary approach, the study incorporates current methods in zooarchaeology alongside taphonomic investigations to explore how animals were used for ritual purposes. By repositioning animals within their central role in ancient sacrificial practice, the results have enriched our understanding of the various ritual activities that took place in Selinus and Akragas, providing a more complete view of how religious beliefs were expressed by the ancient inhabitants of these cities. The analyses have confirmed customary patterns of animal sacrifice as reported by literary and epigraphic sources (e.g. thysia and holocaust) as well as shedding light on less frequent ritual practices followed by ancient Greek communities (e.g. foundation sacrifices). Thanks to the large quantity of remains analyzed, the results go beyond the characterization of the sacrificial practice performed in the two poleis, providing significant insights from an extra-regional perspective involving the wider ancient Greek world. The book constitutes the first synthesis on the zooarchaeology of Greek Sicily, providing a substantial amount of new data which fills a noted void in zooarchaeological research due to the still limited use of faunal assemblage analysis in defining the religious landscape of ancient Greek Sicily.