Abstract: This paper seeks to explore the new dynamics of U.S.–Vietnam security relations from 2011 to 2017. It begins with a review of the attempts before 2011 to establish a foundation for a normal security relationship between the United States and Vietnam, and progresses in the scope and pace of the bilateral relationship in this field. The paper then examines the process of a deepening security relationship between the two countries from 2011 to 2017, focusing on the motivations for increased security cooperation and the developments in five main areas of cooperation, namely maritime security, high-level dialogues, search and rescue, humanitarian assistance and disaster relief, and peacekeeping operations. Finally, this paper looks at the potential and limits of the U.S.–Vietnam security relationship, analyzing the possibilities for building a more balanced and effective security relationship and the limitations of U.S.–Vietnam security cooperation. In conclusion, the authors argue that the years from 2011 to 2017 witnessed new and positive moves in the U.S.–Vietnam security relationship. This is a highly significant development for Vietnam and the United States and an illustration of the fast geostrategic change underway in the Asia–Pacific region in the post–Cold War. Full text available here.