This report presents a comprehensive evaluation of the Cure Violence initiative implemented in Trinidad and Tobago from July 2015 to August 2017. It describes the evaluation’s methods and findings and includes three main components: a process evaluation, impact evaluation, and cost-effectiveness analysis. The process evaluation revealed that local staff successfully implemented some of the key elements of the Cure Violence model in a number of distressed and violent communities in the Port of Spain area. The impact evaluation, based on a series of quasi-experimental designs using multiple independent data sets, found significant and substantial reductions in violence, calls to the police for violent incidents, and gunshot wound admissions in a hospital located near the intervention. Based on these analyses, the report concludes that Project REASON reduced violence in the treatment area. Findings from the cost-effectiveness evaluation showed that Cure Violence cost, on average, approximately US$3,500 to US$4,500 for every violent incident it prevented. Given the profound costs of violence in both human and economic terms, these estimates provide hope not only that violence can be prevented, but also that effective solutions for preventing violence may be affordable.