In recent years, the boundary between “legitimate civil protest” and “riotous behavior” has become one of the major challenges within Iran’s criminal justice system. From the perspective of Islamic jurisprudence (fiqh), social protest—when conducted within the framework of enjoining good and forbidding evil—may be regarded as a form of civic participation. However, when such actions lead to public disorder, property destruction, or threats to social security, they may be criminalized under titles such as baghy (rebellion), ifsād fi al-ard (corruption on earth), or tasbīb (causing harm). This research, through an analytical–comparative approach, examines the fiqhi and legal foundations of criminalizing riotous conduct and demonstrates that principles such as “preservation of the social order” (ḥifẓ al-niẓām), “no harm” (lā ḍarar), and “prohibition of corruption on earth” constitute the core of Islamic penal policy in confronting such acts. In Iranian law, the Constitution recognizes the right to protest under Articles 24 and 27, yet limits it by the requirement to maintain public order. Likewise, the Islamic Penal Code criminalizes violent and destructive acts. The findings suggest that while the fiqhi and legal foundations of Iran are largely coherent, the precise boundary between legitimate protest and riotous behavior still requires clearer legislative definition to prevent the over-criminalization of civil activities.