War is always costly, both in economic terms and in human lives. However, throughout history, leaders have sought to create norms, and eventually international treaties, to reduce its destructive impacts. Although war is never fair, states have agreed to prohibit tactics that lead to undue suffering, including the deliberate targeting of civilians. Unfortunately, these prohibitions have been violated repeatedly. Leaders often try to cover up these violations or blame “bad apples,” individual soldiers at the bottom of the chain of command. Rarely do leaders ever ask the question of why these soldiers committed these acts of violence or what they could have done to prevent them. Using organizational theory, this chapter introduces military socialization and subculture influence as possible explanations for unit participation in war crimes. Better understanding of why these crimes happen may aid policymakers in crafting plans to prevent them.