This thesis analyzes the how the Turkish-American relations altered after the Johnson letter. Referring to US-Turkey association as a “troubled alliance”, this research studies how a once middle-power and a superpower sought cooperation along common interests and how they managed to carry on with their partnership when disagreed. Turkey, as a country whose priority had been to guarantee military aid and development assistance while trying to survive at the onset of the Cold War, sought close ties with the US. It also aspired to balance the hard security threat stemming from the Soviets. Washington capitalized on supporting Turkey thanks to its geostrategic importance as Ankara served as the protector of NATO’s Southeastern flank. However, when the Cyprus issue arose as a major point of discord and the relations reached rock bottom by the Johnson Letter, in addition to few other crises stemming from the Cold War atmosphere, Turkey’s single-minded reliance on the US started to diversify. As Ankara’s foreign policy maneuverability was surging, it adjusted its development aid flow and normalized its ties with the Soviets to a certain extent. The détente period was catalyst for a new Turkish foreign policy trajectory as the tension between Washington and Moscow had been reduced, it served more space for Ankara to navigate on its own course of interests.