The large and increasing burden of mental and substance use disorders, its association with social disadvantage and decreased economic output, and the substantial treatment gaps across country-income levels, are propelling mental health into the global spotlight. The inclusion of targets related to mental health and wellbeing in the UN's Sustainable Development Goals, as well as several national and global initiatives that formed during the past 5 years, signal an increasing momentum toward providing appropriate financing for global mental health. Drawing on the organisational and financial architecture of two successful global health scale-up efforts (the fight against HIV/AIDS and the improvement of maternal and child health) and the organisational models that have emerged to finance these and other global health initiatives, we propose a multi-sectoral and multi-organisational Partnership for Global Mental Health to serve two main functions. First is the mobilisation of funds, including raising, pooling, disbursing, and allocating. Second is stewardship, including supporting countries to use funds effectively, evaluate results, and hold stakeholders accountable. Such a partnership would necessarily involve stakeholders from the mental health field, civil society, donors, development agencies, and country-level stakeholders, organised into hubs responsible for financing, scale-up, and accountability.