This study investigated the symptom profiles of acute stress disorder (ASD) and posttraumatic stress disorder (PTSD) in participants who did and did not sustain traumatic brain injury (TBI), following a road traffic accident. The participants were assessed at three time points: as soon as possible posttrauma as well as at 6 weeks and 3 months posttrauma. At the first assessment, fewer participants from the TBI group recalled feeling fear and helplessness at the time of the trauma, fewer TBI participants reported recurrent intrusive thoughts and images, and more TBI participants reported dissociation since the trauma, relative to the non-TBI group. At the second assessment, fewer participants from the TBI group recalled feeling intense helplessness at the time of the trauma. Fewer TBI participants also reported reliving and physiological reactions on trauma reminders relative to the non-TBI group. At 3 months posttrauma, there was no difference in PTSD symptom profile between non-TBI and TBI groups. Our findings indicate that the presence of TBI is likely to influence the distribution of certain symptoms, but need not be a significant barrier to diagnosing ASD and PTSD.