The independence referendum of the Kurdistan Region was caught in a domestic,regional and international situation.Undoubtedly,the negative reaction of regional and international actors had a significant role in this process.Meanwhile, examining the role of usa as the biggest Global power and an influential actor in the developments of Iraq,which itself has deep relations with the Kurdistan region is very important,and the difference in the action of this actor could have different results in relation to the referendum issue.This research seeks to examine the foreign policy of the usa regarding the independence referendum of the Kurdistan Region in 2017.The questions that this research seeks to answer are:Why was usa unable to present a comprehensive strategy regarding the independence referendum of the Kurdistan Region despite its long-standing relationship with the Kurds? And what were the consequences of this incoherence?The answer to these questions requires examining the internal and external strategic environment affecting the usa foreign policy.Using the theory of "neoclassical realism",this article argues that the systematic limitations as well as the specific perception of foreign policy agents made usa unable to form a clear road map.This caused a strategic vacuum in the region and had consequences such as strengthening the position of the peripheral powers to fill the gap caused by the reduction of usa influence in the region,as well as the isolation of the Kurds in an environment without allies.In this research, descriptive-explanatory method was used and data collection was done by library method as well as interview.