The principle al-yaqīnu lā yuzālu bi al-syak (certainty is not removed by doubt) constitutes one of the major universal legal maxims (al-qawā'id al-fiqhiyyah al-kubrā) that underpins legal reasoning across Islamic jurisprudence. Although extensively examined within the domains of ritual worship and commercial transactions, its application in contemporary Islamic family law remains fragmented and largely descriptive. Existing studies have predominantly emphasized textual interpretation without systematically reconstructing the principle within modern judicial practices involving divorce, maintenance, child legitimacy, marriage registration, and evidentiary standards before religious courts. This article aims to reconstruct the implementation of al-yaqīnu lā yuzālu bi al-syak through an integrated framework combining qawā'id fiqhiyyah, maqāṣid al-syarī'ah, Indonesian positive family law, and judicial reasoning. Employing normative juridical research with conceptual, statutory, case, and comparative approaches, this study analyzes classical fiqh literature, contemporary scholarly works, legislation, Supreme Court decisions, and recent academic publications indexed in Scopus and reputable journals. The findings demonstrate that certainty within Islamic family law should no longer be understood merely as doctrinal certainty derived from classical juristic opinions but must also encompass procedural certainty generated through lawful evidence and judicial verification. The study further argues that the application of this maxim should operate through a proportional evidentiary model that balances textual authority, legal certainty, procedural justice, and protection of vulnerable family members. As its principal contribution, this article proposes a new conceptual model of implementing al-yaqīnu lā yuzālu bi al-syak in Islamic family disputes by integrating normative certainty, evidentiary certainty, judicial certainty, and maqāṣid-based social protection. This reconstruction expands the contemporary relevance of Islamic legal maxims while strengthening judicial consistency and legal protection within modern Islamic family law.