This PhD thesis examines the productive exchanges about state law, Islamic law and customary law that took place between Islamic leaders and other societal actors during an administrative reform process in a Muslim society. Drawing on ethnographic fieldwork between 2006 and 2010 in Aceh, Indonesia, in the context of the end of civil war (1976–2006) and post-tsunami reconstruction, the thesis examines the case of administrative reform in the field of family law, focussing on marriage registration. Civil marriage registration is vital for many women's legal status, which was contentious after war and disaster. The thesis investigates how law-making on marriage registration takes into account such social problems and how those relate to the expectations, political opinions and religious schools of Islamic leaders. The study argues that exploring the importance of Islamic texts is crucial to reconciling different legal perspectives, religious interpretations and claims to regulate family life in law-making processes.