The study of urban armed groups has yet to yield a conceptual framework that can effectively link change (or lack of it) to adaptation. This chapter provides such a framework through a work of disciplinary translation of the logic of evolution through natural selection. The resulting evolutionary/ecological framework allows for the study of change over time with the purpose of explaining urban armed group survival through adaptation to selection pressures. This chapter then verifies the applicability of this framework to cities of the Global South and finally presents the conceptual tools to analyse the territories, relations, and members of urban armed groups.