Objectives: To investigate the contribution of personality and peritraumatic dissociation in the development of posttraumatic stress disorder (PTSD). Method: Victims of road traffic accidents (RTA) were assessed within 2–4 weeks (Time 1) of the accident and again between 4 and 6 months (Time 2). The Eysenck Personality Questionnaire (EPQ) and Peritraumatic Dissociation Experience Questionnaire (PDEQ) were administered at Time 1 and posttraumatic stress symptoms were assessed at Time 2. Results: 265 subjects were assessed at both time points, although neuroticism, psychoticism, and peritraumatic dissociation were significantly correlated with posttraumatic symptoms, only the personality dimensions were independent and significant predictors of subsequent PTSD in a logistic regression. Conclusions: Consistent with the literature personality measures, especially neuroticism, is associated with the development of PTSD. However, peritraumatic dissociation was not found to be an independent predictor of PTSD.