The present article outlines the role of personal, social, and cultural identity in religiously and ethnically motivated terrorism. It is proposed that terrorism represents the confluence of a cultural identity strongly based in collectivism and in fundamentalist adherence to religious or cultural principles, a social identity based in sharp contrasts between one's own group and groups perceived as threats, and a foreclosed and authoritarian sense of personal identity or, less often, a diffused and aimless personal identity. Examples from religious-extremist and ethnic conflicts in which terrorism has been employed are used to illustrate the tenets advanced here. Recommendations for addressing and preventing the threat of terrorism are discussed.