Background: Child marriage is still common in Indonesia both in urban and rural areas. One of possible causes is socio-cultural background. In Madura, the community still stick to culture and customs. Child marriage, one of among others, has become Madurese culture and legalized custom that was inherited to this day as seen in Pagarbatu Village, Sumenep. Objective: The study analyzed the effect of socio-cultural factors on the occurrence of child marriage to girls. Method: This study used a descriptive research design with a qualitative approach. It took place in Pagarbatu Village, Saronggi Sub-District, Sumenep District. The research subjects were women under the age of 18 who engaged in child marriages. Data were collected from April to May 2018. Results: The results showed that socio-cultural factors affect misconduct practices that leads to child marriage, especially among girls. Misconduct practices in child marriage are arranged marriages, age manipulations, witchcraft practices. Child marriage becomes a reason to ease family’s financial burden and also to keep tracing lineage to early ancestors. Religious beliefs are still strong in Madurese community. When females were tranced, they would be married for such mystical experience to get out of trance. Besides, there were other factors of child marriage, such as the lack of community leaders’ roles (village officials), the lack of health workers’ roles, age, education, knowledge, and family economy. Conclusion: There is a relationship between social and cultural factors with child marriage.