Customary land disputes in North Sumatra reflect an ongoing tension between communal land tenure systems and Indonesia’s national civil and land-law framework. Although customary communities and their traditional rights are constitutionally recognised, their protection remains constrained by conditional recognition procedures, formal evidentiary requirements, fragmented institutional authority, and unequal bargaining power. This study aims to analyse the relationship between customary land rights and national civil law and to formulate an integrative framework for resolving customary land disputes. A qualitative socio-legal research design was employed by combining doctrinal legal analysis with empirical investigation. Legal materials included constitutional provisions, agrarian legislation, civil-law principles, land-registration regulations, mediation rules, and relevant judicial decisions. Empirical data were obtained through semi-structured interviews, document analysis, and field observations involving customary leaders, community members, government officials, land authorities, legal practitioners, mediators, and other relevant stakeholders. The findings reveal that customary communities primarily rely on oral histories, genealogical relationships, ancestral occupation, collective cultivation, and customary boundaries, whereas formal institutions prioritise certificates, cadastral maps, permits, and written administrative records. Existing resolution mechanisms remain insufficient because customary deliberation lacks formal enforceability, administrative procedures are institutionally fragmented, and civil litigation often reduces complex communal disputes to conventional ownership claims. This study proposes an integrative framework consisting of community identification, participatory mapping, verification of customary and formal evidence, temporary protection of disputed land, multi-stakeholder mediation, legally binding settlement, administrative registration, and post-settlement monitoring. The study concludes that customary law and national civil law should function as complementary rather than competing legal systems. The proposed framework contributes to legal-pluralist scholarship and provides practical guidance for achieving legal certainty, substantive justice, social legitimacy, and sustainable land governance.