Using as a starting point both feminist critiques of just war theorizing and feminist reconstructions of traditional theoretical approaches to the concept, causes and consequences of war(s), this article looks to outline a feminist approach to re-theorizing war ethics that explicitly accounts for and rejects the current gender biases it creates and reifies. It begins by suggesting that the just war tradition is conceptually and empirically inseparable from gendered notions of warfare, which are gender security and to securitize gender. Therefore, it suggests, war ethics through gender lenses need to be rebuilt from the ground up, paying attention to the heretofore gendered nature not only of war ethics, but also of war justificatory narratives, war practices and war experiences.The article suggests a dialectical hermeneutic framework for feminist war ethics as a basis for theorizing forward from the longstanding feminist recognition that the very concept of warfare is gendered, relying on Robin Schott's (2008) work on witness as a theoretical basis. After outlining this approach generally, the article concludes by sketching out an example of the potential for a feminist approach to war ethics in action, examining the use whole-body image scanners in airport security assemblages. International Politics (2016) 53, 361-384. doi:10.1057/ip.2016.5; published online 11 March 2016Keywords: gender; just war theory; international security; airport security; queer theory; cisprivilege In front of me in line in US customs in August after a long trans-Atlantic flight was someone whose 'papers' did not 'match' their 'correct' sex on their 'ID'. The agent commented loudly that the person must be a gay man to wear a skirt. The woman, clearly tired and scared, was trying desperately to explain -showing a valid US passport, discussing gender transition, and even trying to show likeness to the picture. The account was uncompelling, apparently, though, and I heard the agent identify her as a 'mismatch' and a 'behavior' flag. As they took her away to the mythological small room for questioning, the person was shaking, and clearly about to cry. I quietly checked