This study examines the legal politics of marriage law reform in Indonesia by tracing the historical configurations of legal pluralism and analyzing how each configuration has reshaped the negotiation between Islamic norms, state legal authority, and social transformation within the national marriage law system. This research employs a normative legal method using historical, statutory, and conceptual approaches. Data were collected through library research on legislation, judicial developments, and relevant literature, then analyzed descriptively and analytically. The study finds that marriage law reform in Indonesia is shaped by continuous negotiation between Islamic norms, state legal authority, customary (adat) legitimacy, constitutional rights, and social transformation. This negotiation demonstrates that reform functions not merely as legal modernization but as an ongoing institutional process through which competing religious, legal, and social norms are accommodated within Indonesia's plural legal order. This study is limited to normative and doctrinal analysis and does not include empirical examination of judicial practices, community responses, or the practical effectiveness of marriage law reform across different social settings. This article offers an original contribution by employing legal pluralism as the principal analytical framework to explain how marriage law reform in Indonesia is shaped by the continuous negotiation of Islamic norms, state authority, and social transformation, rather than treating reform merely as a sequence of legislative change.