Despite being a small state in Southeast Asia, Cambodia occupies a central role in the international relations of the region. Conventionally, Cambodia’s foreign policy is explained as one-dimensional in nature, driven by an overriding vulnerability. It is not only materially weak but also situated between its historic rivals of Thailand and Vietnam, which are also larger states with more economic resources. Accordingly, this translates into a lack of autonomy and power in Cambodia’s foreign affairs. The failure of the Association of Southeast Asian Nations (ASEAN) to issue a joint statement for the first time in its history under Cambodia’s chairmanship in 2012 is often cited as primary evidence for this foreign policy predicament. Cambodia was quickly blamed for supposedly representing China’s position on the South China Sea at the fateful ASEAN Summit in exchange for economic support. However, Cambodia’s military agreements with China do not even include provisions for joint action against third parties threatening Cambodian sovereignty, such as from its neighbors. Yet, little attention has been paid to the power dynamics amongst ASEAN members in order to understand the growing regional disunity on the South China Sea at regional meetings. This is unsurprising because Cambodian foreign policy is significantly understudied in political science and Southeast Asian studies. This lecture foregrounds Cambodia’s relations with Southeast Asian states, arguing that Cambodia’s contentious role in the South China Sea conflict can be partly explained by the mis-management of its relations with neighboring Vietnam. In other words, the mainstream narrative about Cambodian foreign policy is misplaced and Cambodia is not the sole culprit in engendering regional instability through its behavior on the South China Sea conflict at ASEAN meetings.