Although NATO was originally created to address regional security concerns, since the end of the Cold War it has expanded its role and partnership to take on new security challenges. In this article, we examine what security gains South Korea could expect to achieve from engaging in NATO’s global partnership security cooperation framework. Our analysis focuses on the possible benefits of security cooperation between the two partners at three different geographic levels, namely, the Korean Peninsula, Northeast Asia, and the global arena. We conclude that South Korea could draw security gains from cooperation with NATO at all three levels. First, partnership with NATO is likely to contribute to peace on the Korean Peninsula. In particular, NATO could participate in post-Six-Party Talks, which have failed to solve the North Korean nuclear problem. NATO would also be able to engage in humanitarian intervention if a crisis arose in North Korea. Second, NATO could contribute to peace in Northeast Asia. Security tensions in the region are currently increasing, as China is pursuing an assertive form of diplomacy while Japan is seeking to actively engage in military conflicts abroad. NATO could also provide support for the United States, which is having difficulty deterring these regional powers. Third, South Korea could cooperate with NATO in peacekeeping operations at a global level. Cooperation with NATO would enhance the effectiveness of South Korea’s peacekeeping operations.