In this chapter, I argue that a feminist reformulation of just war theory is not only generally beneficial but especially important to the just war tradition’s attempts to understand, account for, and monitor the “non-state actors” who have taken the making and fighting of twenty-first-century warfare by storm. Specifically, feminist theory critiques and deconstructs the public/private dichotomy that permits just war theory to privilege the state and reify the state/non-state dichotomy in global politics. This chapter begins by reviewing feminist observations of the gendered nature of the just war tradition. Then, it introduces the “problem” of non-state actors from a feminist perspective, arguing that the gendered nature of just war theory can be identified as a key cause of just war theory’s difficulty dealing with these war-makers and war-fighters. It proposes a feminist reinterpretation of just war standards as the revitalization that the just war tradition needs. It explains this feminist just war theory in terms of breaking down the public/private and rational/emotional dichotomies in ethical thought about war, and replacing them with an approach centered around relational autonomy, political marginality, empathy, and care. It then explores the insights that these reformulations provide for dealing with the non-state actors that currently confound just war theorizing by analyzing the case of a major non-state force in twenty-first-century warfare—terrorism. The chapter concludes by arguing that the added normative strength and explanatory power coming from a feminist perspective is something just war theory needs now more than ever.