This article develops a new paradigm for the study of collaboration by applying the concept to events outside the context of the Second World War. The authors examine three instances of collaboration in twentieth-century mass killings, seeking to situate them within the framework of genocide. Using a multidisciplinary approach, the article questions the validity of explanations of conflict predicated on the existence of binary systems—explanations that appear frequently in comparative genocide studies. The authors relate the decision to participate in mass murder to the history of structural inequality within a given society. The article concludes that, however vague, the concept of collaboration is useful in accentuating a bottom-up approach in the study of genocide.