In the province of Ontario (Canada), over 28,900 adolescents are investigated by child welfare agencies each year because of suspected maltreatment. Exposure to childhood maltreatment represents a major threat to the psychological well-being of young people, particularly in terms of trauma-related stress. The present study investigated trauma symptom profiles among 479 adolescents (13–17 years) involved with the Canadian child welfare system between 2003 and 2010. Latent profile analysis identified three profiles using self-report data from the Trauma Symptom Checklist for Children. Most adolescents (59%, n = 281) were classified into the profile depicting minimal trauma-related symptoms, 30% (n = 144) were characterized by moderate trauma-related symptoms, and 11% (n = 54) were in the profile reflecting severe trauma-related symptoms. Several variables predicted profile membership. Greater severity of sexual abuse and female sex were associated with a greater likelihood of belonging to the severe trauma symptom profile than both the moderate and the minimal trauma symptom profiles. In addition, having society ward status (compared to crown ward) was related to an increased likelihood of belonging to both the severe and moderate symptom profiles relative to the minimal symptom profile. This study provides some insight into the typologies of trauma experienced among child-welfare-involved adolescents and the set of factors which relate to the specific profiles. Findings are important for informing psychological assessment practices, as well as tailored interventions, for adolescents in the child welfare system.