Post-traumatic stress disorder (PTSD) has always been controversial and highly politicized. Here, using a social identity approach, we review evidence that trauma and its aftermath are fundamentally linked to social position, sociopolitical capital, and power. We begin this contribution by demonstrating how a person's group memberships (and the social identities they derive from these memberships) are inherently linked to the experience of adversity. We then go on to consider how it is through group memberships that individuals are defined by their trauma risk and trauma histories-that is, a person's group memberships and their trauma are often inherently linked. Considering the importance of group memberships for understanding trauma, we argue that it is important to see these, and group processes more generally, as more than just "demographic" risk factors. Instead, we argue that when groups are defined by their trauma history or risk, their members will often derive some sense of self from this trauma. For this reason, attributes of group memberships are important in developing an understanding of adjustment and adaptation to trauma. In particular, groups' status, their recourse to justice, and the level of trust and solidarity within the group are all central to the impact of traumatic events on individual-level psychological resilience. We review evidence that supports this analysis by focusing on the exacerbating effects of stigma and social mistrust on post-traumatic stress, and the value of solidarity and strong identities for resilience. We conclude that because of these group-related processes, trauma interweaves the personal with the political and that post-traumatic stress is fundamentally about power, positionality, and politics.