51 論 文 Intra-Regional Border Conflicts and the Institutional Design of ASEAN’s Conflict Management Novri Susan An intra-regional conflict followed by the violent behaviour of conflicting states in Southeast Asia is one of some political issues in the ASEAN regional organizations. Notable cases of intra-regional conflicts are sourced, among others, by border disputes between two or more countries such as Thailand vs Cambodia on Preah Vihear Temple, and Indonesia vs Malaysia on Ambalat Block. However, in the case of Ambalat Block between Indonesia and Malaysia, the escalation has brought military as an instrument of conflict strategy. The last case of the border conflict between Thailand and Cambodia has risen to a violent armed conflict. ASEAN as a regional organization of Southeast Asia countries is often questioned about its strategic role and capacity to manage intra-regional conflicts. Basically, this paper offers a discourse on institutional design and implementation of ASEAN conflict management by looking at the case of border conflicts between its members. This paper is written based on a qualitative method using secondary data from the mass media, research reports, and documentation review. Introduction: Regional Organization and Country Members Border Dispute Several regional organizations like the Arab League, the African Union, SAARC (South Asian Association for Regional Cooperation), and UNASUR (Union of South American Nations) may have different specific organization goals. However, regional organizations are basically formed to establish better international relations among the neighbouring countries. An understandable reason for establishing a regional organization is that neighbours are better in good relations than infraction or wars. The member countries can develop