Protest violence may be one of the most controversial topics in collective action. In this chapter, we provide a comprehensive review of how both protesters and non-participants nevertheless might come to endorse violence as a form of resistance against perceived restrictions on the right to protest in both repressive and less repressive contexts (e.g., democratic systems). Moreover, we shed light on the insufficiency of the pervasive distinction between normative and non-normative collective action that many social psychological works use to characterize street protests. Then, we provide an overview of “Five Dimensions to Unlock Protest Violence” (FiveDi), an interdisciplinary and multi-agent framework drawing upon the Elaborated Social Identity Model of collective action (ESIM), in which protest violence is acknowledged as a meaningful and context-dependent behavior. Finally, we conclude with some recommendations aimed at getting a better understanding of the occurrence and (de-)escalation of protest violence.