Social movement approaches have explored how protest movements transition into terrorist organizations. However, there has been little academic work examining potential causal mechanisms that drive the movement of individuals from nonviolent organizations to violent ones. This study uses priming theory to explain how nonviolent organizations can function as inadvertent gateways that facilitate the movement of individuals into violent organizations. Rather than elaborating on social contacts between nonviolent and violent organizations, priming shifts the analytical focus to socialization processes inside gateway organizations and how they can be exploited by violent organizations through framing. The study also analyzes priming in gateway organizations as a gendered process. Although the examples provided are drawn from the Islamist context, the priming process applies to all religious, far-left, far-right, and nationalist/separatist groups.