Objective Following child trauma, parents are at risk of developing posttraumatic stress disorder (PTSD), either owing to their direct involvement or from hearing of their child’s involvement. Despite the potential impact of a parent’s development of PTSD on both the parent and child, little is known about what may place a parent at increased risk. Method PTSD symptoms were assessed ≤4 weeks, 6 months, and 3 years post-trauma, along with a range of potential risk factors, in a sample of parents of 2–10-year-old children who were involved in a motor vehicle collision. Results and Conclusions Two symptom trajectories were identified: Those parents whose symptoms remained low across all time points and those whose symptoms remained elevated at 6 months post-trauma and declined by 3 years. Subjective threat, thought suppression, and maladaptive cognitions about damage to the child were identified as key predictors of poorer outcomes.