International terrorism has become a major global concern. Several studies conducted in North America and Europe in the aftermath of terrorist attacks reveal that international terrorism represents a significant short-term and long-term threat to mental health. In the present article, the authors clarify the concept and categories of terrorism and then present central findings from studies conducted in the United States and Europe, which mainly focus on negative impacts on mental health, such as emotional stress and PTSD. Furthermore, the authors outline experiments that focus on social interaction processes thought to be triggered by international terrorism and which are assumed to be related indirectly to mental health processes. Next, they highlight the potential positive outcomes on the resilience side, in line with the current theory on posttraumatic growth in adversity. Finally, theoretical and practical implications as well as limitations and future directions are discussed. (Contains 1 note.)