This article reviews the international research literature on the relationship of urbanization, mental health, and social deviancy. Attention is called to the multidisciplinary and multisectoral nature of the topic, and to its associated definitional, conceptual, and methodological issues and challenges. Selected research literature on rural-urban differences in mental health and social deviancy is reviewed. There is little consensus on the causal relationship between urbanization, mental health, and social deviancy, although numerous environmental and social pathogenic processes have been posited and investigated. Data indicate rural and urban milieus can have both pernicious and salutary consequences and that more research is needed to specify critical etiological factors and their relationship to subpopulation characteristics. Suggestions for improving future research efforts are offered, including the use of more complex theoretical models, measurement indices, and data analysis procedures.