Human rights define the most fundamental responsibilities of those who hold power. In the case of the Nazi officials, or those who ordered the Rwandan massacres, we do not need a theory to tell us who was responsible for human rights being violated. The violators were those who authorized and carried out the atrocities, who failed monumentally in their duties toward their victims. The subject of this volume presents a more troubling question: Who, if anyone, is morally responsible for acting to alleviate severe poverty? Here our convictions are much less steady. Are impoverished people responsible for improving their own condition? Or are the leaders of their countries also responsible, or the members of the international community, or we ourselves as individuals? When considering this question we tend to have the kinds of reactions—avoidance of the topic, brief enthusiasm, nagging guilt—that indicate that we perceive several strong and conflicting moral factors, but are unsure how to order these factors so as to reach a firm conclusion. Here is where a philosophical account of responsibility might help. What we want to know is how to determine who, if anyone, has moral responsibility for ensuring that each person’s human human right to an adequate standard of living is secured. What we seek is a general theory that will tell us how to locate responsibility for averting this kind of threat to individuals’ basic well-being. This article sets out a general theory of this kind.