Skeptical worries about moral responsibility seem to be widely appreciated and deeply felt. To address these worries—if nothing else to show that they are mistaken—theories of moral responsibility need to relate to whatever concept of responsibility underlies the worries. Unfortunately, the nature of that concept has proved hard to pin down. Not only do philosophers have conflicting intuitions; numerous recent empirical studies have suggested that both prosaic responsibility judgments and incompatibilist intuitions among the folk are influenced by a number of surprising factors, sometimes prompting apparently contradictory judgments. In this paper, we show how an independently motivated hypothesis about responsibility judgments provides a unified explanation of the more important results from these studies. According to this ‘Explanation Hypothesis’, to take an agent to be morally responsible for an event is to take a relevant motivational structure of the agent to be part of a significant explanation of the event. We argue that because of how explanatory interests and perspectives affect what we take as significant explanations, this analysis accounts for the puzzling variety of empirical results. If this is correct, the Explanation Hypothesis also provides a new way of understanding debates about moral responsibility.