Genocide is the deliberate destruction, in whole or in part, of a people. Typically, it is a crime that is committed by a people. In this essay, I propose an analysis of the concept of an ethnic identity group, which is, I argue, the concept of ethnicity at issue in many important discussions of group rights, group acts, and the moral responsibility of group members for the acts of the groups to which they belong. I develop the account of collective (...) agency presupposed by this analysis and explore its implications for assessments of individual moral responsibility for genocide. I argue, further, that among other advantages over culturalist approaches to questions about group rights, the approach that follows from the concept of an ethnic identity group sheds light on the specific moral wrong of genocide. I reply to individualist objections to the idea that ethnic group membership may be morally significant and argue that morally adequate responses to genocide presuppose acknowledgment of the fact that groups act and are acted upon in morally significant ways. (shrink)