This review synthesizes empirical research in rural mental health services to identify current research priorities to improve the mental health of rural Americans. Using a conceptual framework of the multiple determinants of use, quality, and outcomes, the authors address (1) how key constructs are operationalized, (2) their theoretical influence on the care process, (3) reported differences for nonmetropolitan and metropolitan individuals or within nonmetropolitan individuals, (4) salient issues rural advocates have raised, and (5) key research questions. While the authors recognize that rurality is a useful political umbrella to organize advocacy efforts, they propose that investigators no longer employ any of the multiple definitions of the term in the literature as even intrarural comparisons have not provided compelling evidence about the underlying causes of observed outcomes differences. Until these underlying causes have been identified, it is difficult to determine which components of the nonmetropolitan service system need to be improved.