This article reviews recent theory and research on geographic disparities in mental health and their implications for social work. It focuses on work emerging from the fields of mental health geography, psychiatric epidemiology, and social work, arguing that a wide range of spatial disparities in mental health are important to understand but that of greatest relevance are inequities, or disparities, that violate fundamental norms of fairness and social justice. Research is reviewed on geographic variations in subjective well-being and mental health, on personality (using the five-factor model), and on psychopathology as well as several studies on the disparate implementation of mental health policy and services. Critical is the need to simultaneously assess, on the one hand, differential patterns of mental health conditions and, on the other, the services and policies designed to address them--the fact that considering only one dimension often leads to unintended consequences. Many of the most outstanding disparities have been found to exist at the local level, between towns and neighborhoods, and are based on socioeconomic conditions. This review concludes by discussing the implications of geographic disparities in mental health for allocation decisions and for social work practice, including decisions about the most efficacious mix of services at both the community and clinical practice levels.