While mental health has come to the forefront of public debate during the COVID-19 crisis, it already accounted for one of the largest and fastest growing categories of the global burden of disease prior to the pandemic. The OECD WISE Centre has launched a project applying a well-being lens to population mental health, drawing on the different economic, social, environmental and relational dimensions of people’s lives highlighted by the OECD’s Well-being Framework, and building on synergies with the whole-of-government approaches to well-being now under development in a number of countries. In particular, this project will outline what is needed to improve the quality and availability of comparable data on population-wide mental health status, establish how well-being approaches can serve as additional tool for further policy integration, and help shine a light on areas where more work is needed.