Racial discrimination is a traumatic stressor that increases the risk for posttraumatic stress disorder (PTSD), but mechanisms to explain this relationship remain unclear. Peritraumatic dissociation, the complex process of disorientation, depersonalization, and derealization during a trauma, has been a consistent predictor of PTSD. Experiences of frequent racial discrimination may increase the propensity for peritraumatic dissociation in the context of new traumatic experiences and contribute to PTSD symptoms. However, the role of peritraumatic dissociation in the relationship between experiences of discrimination and PTSD has not been specifically explored. The current study investigated the role of peritraumatic dissociation in the impact of racial discrimination on PTSD symptoms after a traumatic injury, and the moderating role of gender. One hundred and thirteen Black/African American individuals were recruited from the Emergency Department at a Level I Trauma Center. Two weeks after the trauma, participants self-reported their experiences with racial discrimination and peritraumatic dissociation. At the six-month follow-up appointment, individuals underwent a clinical assessment of their PTSD symptoms. Results of longitudinal mediation analyses showed that peritraumatic dissociation significantly mediated the effect of racial discrimination on PTSD symptoms, after controlling for age and lifetime trauma exposure. A secondary analysis was conducted to examine the moderating role of gender. Gender was not a significant moderator in the model. Findings show that racial discrimination functions as a stressor that impacts how individuals respond to other traumatic events. The novel results suggest a mechanism that explains the relationship between racial discrimination and PTSD symptoms. These findings highlight the need for community spaces where Black Americans can process racial trauma and reduce the propensity to detach from daily, painful realities. Results also show that clinical intervention post-trauma must consider Black Americans' experiences with racial discrimination.