KEADILAN DALAM PERLINDUNGAN HUKUM TERHADAP ANAK YANG LAHIR DARI PERKAWINAN SIRINIM.: 22103040153Amalia Nur HidayatiauthorThis research examines the challenges of legal protection and the fulfillment of the principle of justice for children born from unregistered marriages in Indonesia. Although considered theologically legitimate, the lack of marriage registration creates legal vulnerabilities for children, particularly regarding their rights to identity, support, and inheritance. The research problem formulation focuses on: (1) How are legal protection norms and the manifestation of state obligations towards children born from unregistered marriages?; and (2) How is the fulfillment of the principle of justice for children born from unregistered marriages reviewed from the principles of equality and freedom? The research method used is normative juridical with library research. The research approach includes a statute approach and a conceptual approach. Secondary data were analyzed descriptively and analytically using John Rawls' Theory of Justice, Legal Protection Theory, and the concept of State Order. The results of the research indicate that: (1) Legal protection norms for unregistered children are guaranteed in Article 28B paragraph (2) of the 1945 Constitution, the Child Protection Law, and Constitutional Court Decision No. 46/PUU-VIII/2010. However, the state, as a duty bearer, has not fully realized the ideal State Order because administrative policies, such as the SPTJM mechanism in Home Affairs Ministerial Regulation No. 108 of 2019, are still partial "administrative rescue" and are not substantively synchronized with substantive marriage law. (2) Fulfillment of the principle of justice has not reached the standard of equality because the presence of the label "unregistered marriage" in population documents continues to maintain social stigma. Furthermore, the principle of children's freedom is violated because children are still burdened with the responsibility of proving civil relationships through complicated litigation due to their parents' administrative negligence. This study concludes that legal reconstruction is necessary to eliminate discrimination regarding children's status in order to achieve substantive justice.340.1 Perlindungan Hukum2026-01-27UIN SUNAN KALIJAGA YOGYAKARTA;FAKULTAS SYARIAH DAN HUKUMThesis