Purpose of Review Globally, the majority of those who need mental health care worldwide lack access to high-quality mental health services. Stigma, human resource shortages, fragmented service delivery models, and lack of research capacity for implementation and policy change contribute to the current mental health treatment gap. In this review, we describe how health systems in low-and middle-income countries (LMICs) are addressing the mental health gap and further identify challenges and priority areas for future research. Recent Findings Common mental disorders are responsible for the largest proportion of the global burden of disease; yet, there is sound evidence that these disorders, as well as severe mental disorders, can be successfully treated using evidence-based interventions delivered by trained lay health workers in low-resource community or primary care settings. Stigma is a barrier to service uptake. Prevention, though necessary to address the mental health gap, has not solidified as a research or programmatic focus. Research-to-practice implementation studies are required to inform policies and scale-up services. Summary Four priority areas are identified for focused attention to diminish the mental health treatment gap and to improve access to high-quality mental health services globally: diminishing pervasive stigma, building mental health system treatment and research capacity, implementing prevention programs to decrease the incidence of mental disorders, and establishing sustainable scale up of public health systems to improve access to mental health treatment using evidence-based interventions.