The focus of this paper is an influential family of views in the ethics of self-defense and war: views that ground the agent’s liability to be attacked in self-defense in the agent’s moral responsibility for the threat posed (“Responsibility Views”). I critically examine the concept of responsibility employed by such views, by looking at potential connections with the contemporary literature on moral responsibility. I start by uncovering some of the key assumptions that Responsibility Views make about the relevant concept of responsibility, and by scrutinizing those assumptions under the lens of more general theorizing about responsibility. I identify an important conflict that arises at that point. The problem is that the concept presuppos...