Mental health is critical to personal well-being, interpersonal relationships, and successful contributions to society. Mental health conditions consequently impose a high burden not only on individuals, families and society, but also on economies. In Jamaica, mental health conditions are highly prevalent and major contributors to morbidity, disability, and premature mortality. Encouragingly, with timely and effective treatment, individuals suffering from mental health conditions can lead productive and satisfying lives. This publication, the first of its kind, provides evidence and guidance to support the development, financing, and implementation of mental health interventions in Jamaica. Specifically, it estimates the return on investment (ROI) from scaling up treatment for anxiety, depression, and psychosis. The results from this analysis show that Jamaica can significantly reduce the health and economic burden of mental health conditions by investing in cost-effective recommended interventions designed to improve mental health.