EU trade strategies which include multilateralism, bilateralism/inter-regionalism, unilateralism, and protectionism have displayed different trends in different time periods. Regarding the determinants of EU trade strategies, while institutionalist approach points to the roles played by core EU institutions, pluralist approach draws attention to the influence of domestic interest groups. Systemic approach, on the other hand, underlines the impact of external constraints or opportunities. Nevertheless, neither of these approaches can provide a complete explanation as each of them focuses on the impact of one factor. The aim of this thesis is to investigate the changing dynamics and determinants of EU trade strategies by developing a more interactionist approach. For this purpose, firstly, main arguments of the previous approaches utilized in the analysis of EU&rsquo / s external trade policy are critically reviewed. Later, all the major factors proposed by previous approaches are brought together in an interactionist manner in order to demonstrate that a direction of influence exists among these factors and they each play a distinct role in the determination of EU trade strategies. Secondly, reasons behind different trends displayed by EU trade strategies throughout history are investigated by utilizing the interactionist model for three major periods: 1958-1995 / 1995-2000 / 2000-present. The analysis reveals that in all three periods, external factors always drive the EU to reconsider its trade strategies while their specific content is rather shaped by domestic dynamics.