Turkey joined North Atlantic Treaty Organization (NATO) in 1952 as part of the first enlargement of the organization, and the relationship has lasted until the present day despite some difficulties. Although both sides are committed to the alliance and gain mutual benefits from it, the relationship has been fluctuating. This chapter argues that Turkey’s cooperation with its allies is mainly a result of its changing security concerns related to the new balance of power in the region and to Syria spill-over effects. The Turkish attitude toward NATO began to change and this became more visible after the end of the Cold War. To better understand the new dynamics, two factors must be considered: the changes that occurred domestically and the new interpretation of international security. Turkey proves to be committed to balance its position as an ally of the United States, NATO member, and at the same time as a promoter of the Astana group with Russia and Iran.