The international community, led by the United States, has long sought North Korea’s denuclearization; however, North Korea has effectively become a nuclear-armed state, and the prospects for its denuclearization appear low. Nevertheless, efforts toward North Korea’s denuclearization must continue, as long-term peaceful coexistence between a nuclear-armed North Korea and a nonnuclear South Korea is not only unrealistic but also risks triggering a nuclear domino effect in the region. In this context, analyses of cases in which international denuclearization efforts have achieved some success—such as South Africa’s renunciation of nuclear weapons, Libya’s termination of its nuclear program, the abandonment of nuclear weapons by Ukraine and other former Soviet republics, and Iran’s agreement to halt its nuclear weapons development—can provide valuable practical lessons for North Korea. In these cases, the creation of a stable security environment proved more important than economic incentives, and shifts in leadership perceptions were decisive in enabling major policy changes. The international community should focus on improving the security environment on the Korean Peninsula and in Northeast Asia to ensure that North Korea does not fear for its survival even if it abandons nuclear weapons, while simultaneously monitoring political changes within North Korea.