The global burden of neuropsychiatry diseases and related mental health conditions is enormous, underappreciated and under resourced, particularly in the developing nations. The absence of adequate and quality mental health infrastructure and workforce is increasingly recognized. The ethical implications of inequalities in mental health for people and nations are profound and must be addressed in efforts to fulfil key bioethics principles of medicine and public health: respect for individuals, justice, beneficence, and non-malfeasance. Stigma and discrimination against people living with mental disorders affects their education, employment, access to care and hampers their capacity to contribute to society. Mental health well-being is closely associated to several Millennium Development Goals and economic development sectors including education, labour force participation, and productivity. Limited access to mental health care increases patient and family suffering. Unmet mental health needs have a negative effect on poverty reduction initiatives and economic development. Untreated mental conditions contribute to economic loss because they increase school and work absenteeism and dropout rates, healthcare expenditure, and unemployment. Addressing unmet mental health needs will require development of better mental health infrastructure and workforce and overall integration of mental and physical health services with primary care, especially in the developing nations.