Marriage registration in Islam is not a condition and pillar of marriage, but it often leads to legal consequences for unrecorded marriages (siri/unregistered marriage). These consequences may affect the status of children, the wife, inheritance, and other matters. To avoid such issues, laws have been established to regulate and legalize marriages, ensuring legal certainty. Law Number 22 of 1946 concerning Registration of Marriages, Divorces, and Reconciliation, as well as Law Number 1 of 1974, revised as Law Number 16 of 2019 concerning Marriage, clearly state the regulations for marriage. Marriage registration is crucial for ensuring the legal validity of a marriage event. According to the Jumhur Ulama, a marriage is considered valid if it fulfills the essential pillars and conditions, including the groom, the bride, guardians, witnesses, ijab and qabul (consent exchange), and dowry (Mahar). Marriages that do not meet these legal requirements are often referred to as private marriages, unregistered marriages, contract marriages, or mistresses. Marriage registration is of great importance in the study of marriage, both conceptually and operationally, as it is a legal requirement for marriage in Indonesia. The purpose of registering marriages and divorces is to facilitate state administration, ensuring that rights arising from the marriage, such as issuing birth certificates and family cards, require a marriage certificate as valid proof of the marriage event.