Criminal governance—when organized criminal groups regulate the behavior of local residents—has become one of the most consequential challenges confronting contemporary Latin American societies. In the areas where criminal groups operate, they often regulate economic, social, and political life, establishing parallel institutions, resolving disputes, extracting revenue, and offering security and services. Once primarily associated with fragile states, criminal governance has spread across a wide range of contexts, including relatively strong and democratic states in Latin America. This policy document synthesizes three decades of interdisciplinary research on the topic, drawing on 169 academic studies published since 1990 and original fieldwork conducted by the authors across several Latin American countries. It explains how criminal groups govern; presents competing theories about when and why they take on governance functions; and assesses the social, political, and economic consequences of these local regimes. It then reviews evidence on key policy responses—including militarized enforcement, community-based interventions, and negotiation—highlighting their strengths, limitations, and unintended effects. The document concludes with recommendations for designing more effective policies to confront criminal governance and mitigate its harms. It also outlines avenues for future research and data collection.