Research on civil war mobilization emphasizes armed group recruitment tactics and individual motivations to fight, but does not explore how individuals come to perceive the threat involved in civil war. Drawing on eight months of fieldwork with participants and nonparticipants in the Georgian-Abkhaz war of 1992–93, this article argues that social structures, within which individuals are embedded, provide access to information critical for mobilization decisions by collectively framing threat. Threat framing filters from national through local leadership, to be consolidated and acted on within quotidian networks. Depending on how the threat is perceived—whether toward the self or the collectivity at its different levels—individuals adopt self- to other-regarding roles, from fleeing to fighting on behalf of the collectivity, even if it is a weaker actor in the war. This analysis sheds light on how the social framing of threat shapes mobilization trajectories and how normative and instrumental motivations interact in civil war.