The International Court of Justice (ICJ), as the principal judicial organ of the UN, plays an important role in peaceful resolution of international disputes. Traditionally, relations between Islamic law states, international law, and courts have been relatively tense due to the inherent link between Islamic law and the Islamic faith. Yet, several Islamic law states recognize the ICJ’s compulsory and compromissory jurisdiction. This article asks: Why do some Islamic law states extend support to the International Court of Justice, while others turn away from the Court? I argue and empirically demonstrate that specific characteristic of Islamic law can explain variation of Islamic law states’ preferences towards the ICJ. After providing original data on the characteristics of Islamic legal structures, I systematically compare pertinent rules of international law and Islamic law, focusing on similarities and differences between the two. Islamic law features such as respect for legal scholarship and peaceful resolution of disputes are compatible with principles embraced by the ICJ. Islamic law states that incorporate these norms are supportive of the Court. In contrast, Islamic law states that directly adopt sharia as the law of the land and incorporate sharia in their education systems are less open to the ICJ’s adjudication.