Only a minority with mental disorders worldwide receive treatment with negligible coverage of interventions to prevent associated impacts, prevent mental disorders or promote mental well-being. Reasons include insufficient public mental health (PMH) skills and training. An electronic search found limited availability of PMH courses globally. Improved access to PMH training informed by a core curriculum will support sustainable reduction of mental disorders, promotion of population mental health well-being and broad associated impacts across sectors. Regular assessment of PMH training coverage and impact will support sustainable progress.