Mental health systems in many countries are seriously under-developed, yet mental health problems not only have huge consequences for quality of life, but--particularly in low- and middle-income countries--contribute to continued economic burden and reinforce poverty. This paper discusses economic barriers to improving the availability, accessibility, efficiency and equity of mental health care in low- and middle-income countries. Six sets of barriers are identified: an information barrier, resource insufficiency, resource distribution, resource inappropriateness, resource inflexibility and resource timing. Overcoming these barriers will be a major task, although there is no shortage of suggestions for action. The paper discusses broadening the evidence base, improving mental health literacy, tackling stigma, improving financing mechanisms, prioritizing and protecting mental health care budgets, emphasizing mental health promotion through the development of resilience, exploring routes to improved equity, experimenting with new arrangements for purchasing and delivering services, improving coordination between agencies and professionals at both macro- and micro-levels, building alliances between public and private sectors, and training and mobilizing primary care services to improve identification and treatment of mental health problems.