The expansion of urbanization, the complexity of social relations, population density, and the transformation of criminal methods have turned urban crime into one of the major challenges of criminal justice systems and urban governance. Traditional responses based on punitive repression and the exclusive intervention of the state are no longer sufficient for the effective control of urban crime, since many criminogenic factors emerge within the social, economic, cultural, and environmental contexts of urban life. In this regard, participatory criminal policy, as a contemporary model of criminal policy, emphasizes the involvement of citizens, the police, local institutions, and civil society in crime prevention. Using a descriptive-analytical method and a criminal law and criminological approach, this article examines the role of citizens and the police in preventing urban crime. The findings indicate that citizens’ participation through reporting, informal social control, neighborhood-based cooperation, enhancement of social capital, and civic accountability can significantly reduce criminal opportunities. Furthermore, the police, through community policing, problem-oriented policing, and preventive policing, can improve the effectiveness of criminal policy by strengthening public trust, analyzing crime hotspots, and maintaining continuous interaction with society. Nevertheless, participatory criminal policy faces challenges such as the risk of violating privacy, discriminatory social control, arbitrary citizen intervention, mutual distrust between the police and the community, and insufficient public education. The article concludes that participatory criminal policy can be effective in preventing urban crime only when it is based on legality, accountability, public trust, protection of citizens’ rights, and institutional oversight.