Trade liberalization has been one of the most important structural reforms implemented in developing countries since 1980s. Trade openness, defined as the elimination of restrictions on international trade, is expected to stimulate economic growth by increasing efficiency in resource allocation. However, empirical evidence on the relationship between trade openness and economic outcomes presents mixed results. This study examines the relationship between trade openness and external debt for Turkey using annual data for the period 1980-2011. The results of the cointegration analysis suggest that trade openness and external debt are cointegrated in the long-run. Furthermore, Granger causality analysis reveals that there is a unidirectional causal relationship running from trade openness to external debt.