This paper proposes an interdisciplinary research framework for developing mental health policy in countries where a multisectoral approach to population mental health is not yet on the policy agenda. The proposed mental health policy research framework contains two structural elements: research on the policy content and policy process dimensions. The content dimension defines mental health policy as being a multisectoral policy encompassing positive mental health for all, the prevention and treatment of mental disorders, and the social and human rights consequences of poor mental health. The process dimension is based on the cyclical model of policy processes as described by Kingdon’s theory of agenda-setting and Rochefort’s analysis of the factors which affect mental health policy-making. The framework presents an innovative approach to researching mental health policy, bringing a more interdisciplinary focus and an explicit emphasis on policy-making.