High-quality data on funding for mental health research are essential to mapping funding levels, identifying gaps in the funding landscape, and tracking the impact of research funding. To date, quantitative analyses of research funding in mental health have been restricted in scope. In this Health Policy paper, we present a comprehensive analysis of grant funding for mental health research as a starting point for discussion among stakeholders globally. We drew on a major international research database and used existing definitions and automated classification tools for mental health research. Our analysis shows a flat and stable trend over the years 2015-19 and highly unequal geographical distribution of funding, and reveals patterns of funding across different conditions and across the research spectrum. Improvements in data availability and quality, in the definitions delineating mental health research from other areas, and in automated classification tools are needed to ensure funders and policy makers can fully rely on the data and generate bespoke analyses as needed. We argue that collaborative reporting of funding for mental health research globally could help to inform and evaluate efforts to increase investments, to improve strategic dialogue, and to achieve the best possible allocation of finite resources.