Positive mental health is recognised as a key resource for population well-being and the social and economic prosperity of society. This paper provides an overview of current concepts of positive mental health and its contribution to the health and well-being of society. Frameworks for promoting mental health are presented, together with an overview of key concepts and principles underpinning this multi-disciplinary area of practice. Drawing on empirical studies, the article reviews the determinants of positive mental health across the lifespan. Enhancing factors for promoting mental health at the structural, community and individual levels are identified. The growing evidence base on the effectiveness of mental health promotion interventions is discussed, and the implications of addressing the psychosocial determinants of mental health for policy and practice are considered.