Violent extremism represents a serious challenge to open and democratic societies. This article presents a framework for understanding violent extremism in the context of “lone-wolf” attacks in Western societies. The framework combines social, political, and psychological factors and highlights the importance of integrating the available evidence from multiple disciplines to develop cogent, effective policy. Specifically, in addition to a broad survey of motivational factors, the article draws on terror management theory to provide insight into the interaction between religiosity and violence.