A long-standing territorial dispute between Thailand and Cambodia is resurfacing, raising concerns about the adherence to international law. For almost eight decades, the international legal order has prohibited the acquisition of territory through force. This principle, enshrined in the UN Charter, is now being challenged by Thailand’s continued occupation of Cambodian territory. The situation underscores the importance of respecting sovereignty and territorial integrity, even within regional blocs like ASEAN. Allowing such actions to persist would undermine the rules-based international system. The argument that any ASEAN member is exempt from these laws is legally untenable. Resolving this issue through peaceful and legal means is crucial for regional stability and the upholding of international norms.