There is compelling evidence from high-quality studies that mental health promotion and primary prevention interventions can reduce the risk of mental disorders, enhance protective factors for good mental and physical health, and lead to lasting positive effects on a range of social and economic outcomes. This paper reviews the available evidence in order to guide the implementation of mental health promotion and prevention interventions in the Eastern Mediterranean Region. The paper identifies a number of priority areas that can generate clear health and social gains in the population and be implemented and sustained at a reasonable cost. The interventions cover population groups across the lifespan from infancy to adulthood and include actions delivered across different settings and delivery platforms. "Best practices" were identified as interventions for which there is evidence not only of their effectiveness but also of their feasibility within resource constraints. The implications of the findings for capacity development are considered.