A challenge faced by many countries is to provide adequate human resources for delivery of essential mental health interventions. The overwhelming worldwide shortage of human resources for mental health, particularly in low-income and middle-income countries, is well established. Here, we review the current state of human resources for mental health, needs, and strategies for action. At present, human resources for mental health in countries of low and middle income show a serious shortfall that is likely to grow unless effective steps are taken. Evidence suggests that mental health care can be delivered effectively in primary health-care settings, through community-based programmes and task-shifting approaches. Non-specialist health professionals, lay workers, affected individuals, and caregivers with brief training and appropriate supervision by mental health specialists are able to detect, diagnose, treat, and monitor individuals with mental disorders and reduce caregiver burden. We also discuss scale-up costs, human resources management, and leadership for mental health, particularly within the context of low-income and middle-income countries.