<![CDATA[Unregistered marriages (nikah siri) continue to create significant legal challenges in Indonesia, particularly concerning the legal status and civil rights of children. Although Indonesian law recognizes the religious validity of marriage, the absence of official registration often results in legal uncertainty regarding children's civil status, paternal affiliation, inheritance rights, guardianship, maintenance, and access to constitutional protections. This study aimed to analyze the legal implications of unregistered marriages on the status of children within the Indonesian legal system and to evaluate the effectiveness of legal protection following Constitutional Court Decision Number 46/PUU-VIII/2010. The study employed a normative legal research method using statutory, case, conceptual, and comparative approaches. Legal materials were obtained through library research from legislation, Constitutional Court decisions, international legal instruments, and recent scholarly publications and were analyzed qualitatively using doctrinal legal interpretation. The findings indicate that marriage registration serves not merely as an administrative requirement but as a fundamental legal mechanism that ensures legal certainty and strengthens the protection of children's constitutional and civil rights. Furthermore, Constitutional Court Decision Number 46/PUU-VIII/2010 has expanded legal protection by recognizing civil legal relationships between children born from unregistered marriages and their biological fathers, subject to legally admissible proof. However, inconsistencies in legal interpretation and implementation continue to hinder effective protection. The study concludes that harmonizing family law and administrative regulations is essential to ensure legal certainty, equal protection, and the best interests of children.]]>
