This research examines the position of children from mixed marriages between Minangkabau and Javanese ethnicities in Lubuk Kilangan Sub-district, Padang City, based on the viewpoint of customary stakeholders. Problems arise due to differences in kinship systems: Minangkabau adheres to a matrilineal system, while Java is bilateral. This difference affects children's identity, inheritance rights and involvement in adat. The method used is qualitative ethnography with a participatory observation approach, in-depth interviews with traditional leaders, and document studies. The results show that maternal lineage is the main factor in determining the position of children. Children of Minangkabau mothers are traditionally recognized, have rights to high pusako, and are involved in traditional activities. In contrast, children of Javanese mothers are considered “nan indak basuku” (not tribal) and do not have customary inheritance rights, even though the father is Minang. The status of the child is determined through customary deliberation by the customary leader. However, the division of property from the family business can be done based on the principles of Islamic law. The research reveals the tension between inclusive national legal principles and strict customary rules, as well as the family's efforts to adjust to customary forms of exclusion. The research recommends adjustments to civil registration policies, improved cross-cultural communication and an evaluation of the role of customary stakeholders to ensure children's rights in a multicultural society.