This dissertation is an examination of trade and socio-political development in Iron Age (500 BC AD 500) mainland Southeast Asia through the analysis and comparison of stone and glass beads from sites in Cambodia and Thailand. The primary research objective is to identify trade and interaction networks in mainland Southeast Asia during the Iron Age and understand how these trade networks were associated with emerging socio-political complexity in the Mekong Delta during this period. This topic was addressed through morphological, contextual, and compositional analysis of agate/carnelian, garnet, and glass beads. Using these objects I identified distinct patterns in the distribution of stone and glass beads on two different scales: within individual sites in Cambodia and Thailand and over time and across the region of mainland Southeast Asia. I then linked these bead distribution patterns to changing patterns of socio-political and economic organization in the Mekong Delta. The results of this research indicate that the types of agate/carnelian and glass beads and the mechanics of trade and exchange changed over time. During the early Iron Age in the late centuries BC Period 1 Type agate and carnelian beads and potash glass beads appear to have been exchanged through a pre-existing coastal exchange networks between specific settlements. However, some communities, specifically people living at Angkor Borei and sites in the MekongDelta do not appear to have been participating in this network. Instead, the analysis of glass and stone bead data reveal that the Mekong Delta and other communities were not entering into long-distance bead exchange networks until the early centuries AD, as trade with South Asia was intensifying. New types of beads, including Period 2 Type agate and carnelian beads and high-alumina soda glass beads eventually came to be traded in these networks. I argue that the distribution patterns of these new stone and glass bead types can be seen as proxies for expanding socio-political and economic influence between elites in the Mekong Delta and communities further inland.