This paper will examine the transformation of NATO-Russia relations from the post-Cold War stage to the 2014 Crimea crisis. It will specify how NATO's several eastward expansions contributed to the shift of Russia's foreign policy and their bilateral relationship. The analysis will begin with the optimism the Russian side held after the Cold War and the establishment of bilateral cooperation acts such as the Basic Act and the Partnership for Peace. The paper will also analyze the color revolutions that occurred in Ukraine and Georgia, as well as the subsequent 2008 Russo-Georgian War, to examine how Russia's foreign policy has shifted during the 2000s. The paper will then shed light on the Ukrainian crisis in 2014, which ultimately ended the cooperation between Russia and NATO. Through case studies, this paper will examine the shift of Russias foreign policy in the context of NATO's eastward expansion, which has reshaped the geopolitical landscape of Eastern Europe in the past decades.