Following resettlement in Western countries, unaccompanied refugee minors (URM) are at risk of developing posttraumatic stress disorder (PTSD). It is unclear to what extent PTSD in this group may become manifest at later stages following resettlement and which factors are associated with late onset. We examined data from URM collected 1 (T1) and 2 years (T2) following resettlement for differences between groups with no PTSD, PTSD at T1, and late-onset PTSD (at T2 only) using multinomial regression and path analysis. Of the children and adolescents (ages 12-18) completing both assessments (N = 554), 223 (40%) met criteria for PTSD at T1, and 88 (16%) endorsed late-onset PTSD. Late-onset PTSD was associated with traumatic event exposure, older age, and low education. In the late-onset PTSD group, the predictive effects of traumatic event exposure on symptom severity at T2 were fully mediated by depression and anxiety symptoms at T1. These results suggest that late-onset PTSD is a clinically relevant problem among URM that may be heralded by early depression and anxiety symptoms.