Genocide, often referred to as the “crime of crimes,” has produced hundreds of millions of murdered, raped, sexually assaulted, forcibly displaced, kidnapped, mutilated, and robbed victims. While criminologists are dedicated to explaining these types of crimes and social group conflict more broadly, they typically apply these crimes to interpersonal and intranational criminal acts of violence. As a result, criminologists have failed to incorporate genocide adequately into their research agendas leaving the “crime of crimes” neglected and undertheorized by the discipline. There are notable exceptions, including critical criminologists who frequent condemn mainstream criminology for not considering the role of the state as a criminal actor. Furthermore, recent publications by criminologists that focus on the genocide in Darfur and the 1994 genocide in Rwanda offer hope that historical neglect is declining. Nonetheless, criminology has been slow moving and nearly silent toward incorporating genocide within its disciplinary boundaries. Criminologists possess the theories and methods necessary to make valuable contributions to documenting, describing, and explaining “the crime of crimes” and to understanding the consequences of genocidal victimization.