The widespread availability of illegal firearms fuels crime and violence in Latin America and the Caribbean. This study reviews the evidence on the link between the proliferation of firearms, organized crime, and levels of violence in the region. Stylized facts and empirical evidence show a strong correlation between gun proliferation and homicide rates. Although evidence on causality is limited, studies that have addressed this question suggest that greater availability of guns increases homicidal violence. However, knowledge gaps persist that call for better data and more research on the availability and markets of illicit weapons. This document also examines how criminal groups take advantage of access to weapons to consolidate their territorial control and escalate different forms of violence, and how the convergence of these groups with drug trafficking feeds "drugs-for-guns" circuits that intensify violence and criminal governance. In view of this, the need to strengthen internal coordination and international cooperation to regulate firearms and their markets is emphasized. Reducing illicit proliferation and violence requires a comprehensive approach that combines immediate measures (confiscation operations, disarmament campaigns) with long-term structural reforms (stricter arms control laws, stronger border and official arsenal controls, and dismantling trafficking networks). Only a sustained response, and articulated between countries, will make it possible to durably reduce the illicit flow of arms in the region.