Background Diminished physical and mental health-related quality of life (HRQoL) is a common consequence of road traffic crash (RTC) injury. This study aimed to (a) determine the probable recovery trajectories in physical and mental HRQoL; (b) examine the impact of posttraumatic stress disorder (PTSD) on HRQoL scores within these trajectory groups; and (c) examine the influence of predictor covariates on trajectory group membership. Methods 336 (63% female, Mage =44.72; SD =14.77) injured RTC survivors completed the SF-36v2 at approximately 6, 12, and 24 months after sustaining a RTC injury. Participants also completed telephone interviews to assess prior history of psychological disorder and current PTSD at each wave. Results Three trajectories were identified for SF-36v2 Physical Component Score (PCS): ”gradual recovery” (27.3%);”low but improving” (54.7%); and”severe and chronic” (17.9%). Four trajectories were defined for SF36v2 Mental Component Score (MCS): “unaffected” (19.1%);”severe but improving” (24.1%);”severe and declining” (17.3%); and”low but improving” (39.5%). A PTSD diagnosis significantly reduced SF36v2 component scores only in trajectories associated with poorer outcome. Age was predictive of trajectory group membership for PCS, whereas injury severity was predictive of trajectory group membership for MCS. Limitations Use of a compensation seeking sample affects generalizability to the general RTC population. Conclusions This study identified a concerning subgroup of individuals who have chronic and/or declining physical and mental HRQoL that can be impacted by a diagnosis of PTSD. The development of interventions with a special focus on associated psychological injury is needed to improve the HRQoL of at-risk individuals following RTC injury.