In case about child custody disputes are one of the most influential issues in family law that often cause long debates, especially in the context of divorce case. Child custody is a central issue in divorce case that have a wide impact, not only for parents, but also for the psychological development of the children involved. One interesting case to analyze is the child custody dispute experienced by Tsania Marwa and her ex-husband, Atalarik Syah. This case is not just only in the public spotlight because it involves public figures, but also has a profound impact on the issue of gender justice in the legal process in Indonesia. In analyzing the legal certainty of court decisions regarding the child custody dispute in the case study of Tsania Marwa, the author uses a qualitative descriptive methodology in managing all sources used in this writing. Qualitative methodology refers to research methodology that produces analytical descriptive data, the data is reviewed in accordance with applicable legal theory and laws and regulations, such as Article 41 of Law Number 1 of 1974 concerning Marriage, Article 14 of Law Number 35 of 2014 concerning Child Protection, and Article 105 of the Compilation of Islamic Law (KHI), which are relevant in revealing the problem. So that at the end of this writing it is found that the Decision of the Constitutional Court (MK) Number 140/PUUXXI/2023 provides a stronger legal basis by emphasizing that the act of taking a child by force by a party who does not have custody rights can be subject to criminal sanctions in accordance with Article 330 paragraph (1) of the Criminal Code, in addition, the implementation of child custody rights requires firmer and more coordinated support from all related parties. The legal system must ensure that the best interests of the child remain the top priority, while still respecting and protecting the rights of the custody holder. In the case of Tsania Marwa, firmness in implementing the law is the main key to ensuring that her rights are implemented fairly and in accordance with the principle of legal certainty.