This research examines the law of inheritance which is the rule governing human relations regarding inheritance. Inheritance between a Muslim and people of different religions of course there are differences. This research uses library research with a normative approach. The data was obtained by collecting from several sources, such as books and articles, which were then analyzed normatively using the basis of Islamic law, such as the Koran and hadith. The result of this research is that there are decisions of the Supreme Court which provide provisions regarding inheritance to heirs of different religions through a mandatory will with the same level as the heirs of different religions should receive in the Islamic inheritance system. Determination of the validity of the obligatory will for heirs of different religions is a form of creating benefit and peace, especially in a family.