Although glass beads were found in large quantities in Southeast Asia during the Iron Age and into the first millennium CE, glass artifacts from the Angkorian period (ninth–fifteenth centuries CE) are less common and have not been as well-studied. This paper presents the results of an analysis of 81 glass beads and artifacts from the ninth-century royal capital of Hariharālaya and later (twelfth–fourteenth centuries CE) contexts from the walled city of Angkor Thom. Compositional analyses using laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) have identified glass belonging to three broad compositional groups. The earlier Hariharālaya sites have numerous glass beads and vessel fragments made from vegetal soda glass, associated with Middle Eastern production, as well as high-alumina mineral soda glass of a sub-type frequently found at Iron Age sites in Southeast Asia and likely produced in South Asia. Beads from the later-period sites within Angkor Thom are primarily lead glass, associated with Chinese glass production, and different sub-types of high-alumina mineral soda glass that have also been found at sites in Southeast Asia dating from the fourteenth to the nineteenth centuries CE. A small number of beads from Angkor Thom also have a vegetal soda composition distinct from beads at Hariharālaya. The results of this study provide a new type of evidence for elite participation in broader regional exchange networks during the Angkorian period.