Previous studies have recognized that the benefits from foreign direct investment (FDI) to recipient countries can only be realized when those countries have reached a certain level of financial development. However, the dynamic interrelationships among FDI, financial development, and real output, including the long-run equilibrium as well as causality, have not been analyzed. This paper overcomes this major shortcoming by applying recent advances in panel cointegration and panel error correction models for a set of 37 countries using annual data for the period 1970-2002. For the first time, we explore the directions of causality among FDI, financial development, and economic growth and obtain solid, convincing evidence of a fairly strong long-run relationship. Furthermore, the financial development indicators have a larger effect on economic growth than does FDI. From the panel causality tests, while the evidence of a short-run relationship is weak, that of a long-run relationship among the variables is unequivocal. Overall, the findings underscore the potential gains associated with FDI when coupled with financial development in an increasingly global economy.