<![CDATA[A marriage agreement is a legal instrument that enables spouses to regulate the property consequences of marriage. Legal uncertainty may arise when a marriage agreement has been executed in an authentic deed but has not been registered with the competent marriage registration authority and is subsequently invoked in a claim for the division of marital property following divorce. This study examines the legal status and legal certainty of an unregistered marriage agreement deed in disputes over property division following divorce. This research employs a normative juridical method using primary, secondary, and tertiary legal materials, with statutory, case, analytical, and conceptual approaches. The legal materials were collected through library research and analyzed qualitatively using grammatical and systematic interpretation. The analysis is based on Jan Michiel Otto’s Legal Certainty Theory and Subekti’s Consensualism Theory. The findings demonstrate that an unregistered marriage agreement deed remains legally binding between the spouses if it satisfies the requirements for a valid agreement and does not violate applicable law, religion, or morality. The authentic deed provides evidentiary force concerning the property regime agreed upon by the spouses. However, failure to register the agreement affects its enforceability against third parties because registration serves a publicity function. Therefore, legal certainty between the spouses derives from the agreement’s binding force, the evidentiary value of the authentic deed, and judicial enforcement, while legal certainty for third parties requires effective and consistent registration.]]>
