In recent decades, increased research on post-Roman Sicily has made it possible to better understand the crucial role that the island played within the Mediterranean area both in the late Roman and medieval periods. The study of ceramics has revealed important manufacturing and commercial aspects that affected Sicily during this time. This research used glass as another indicator to investigate questions of production and circulation of commodities between the 5th and 11th centuries CE. In the context of two European Research Council research programmes ('Sicily in Transition' and 'GlassRoutes'), the first systematic study of Sicilian glass assemblages was conducted to explore their chrono-typological and compositional characteristics. The chronological arc includes the fundamental transformations of the ancient glass industry and the establishment of new glassmaking technologies in the Western Mediterranean and Europe. Combining the archaeological and analytical data, the temporal and geographical evolution of glass consumption and supply within the island was defined, revealing how regime changes affected the availability of vitreous materials. More specifically, in order to highlight differences and similarities between different parts of the island through time, the results of the centraleastern rural site of Villa del Casale (Piazza Armerina -Enna Province) and the western city of Mazara del Vallo (Trapani Province) are compared. The analytical data from Mazara del Vallo illustrate a continuity in glass supply from the Levantine coast at least until the 7th century. Moreover, the typologies are consistent with those already published for the Western Mediterranean area. The Islamic conquest introduced new glassmaking techniques with possible local production of soda plant ash glass as early as the 9th/10th century. Furthermore, the typologies and analytical results point to the integration of Sicily into the wider Fatimid markets.