The new global and regional realities which had emerged before World War II made it vital for Turkey to develop a strategy in foreign policy in line with the current conditions regarding the Straits. The administrators of the Republic of Turkey carried out national interest-based and realistic policies against the actors of the day who thought that the privilege to be obtained in the Straits would lead to geostrategic results beyond their time. Realism offers an important analytical framework in explaining this foreign policy strategy implemented to ensure Turkey's own security. This paper focuses on the objective conditions, alliance relations and policies during the power struggle over the Straits before World War II. In the study, the politics of the period, relations of interest and diplomatic relations are examined by use of Turkish / British archive documents and secondary sources.