Homelessness itself is traumatic, and more than half of homeless young adults have also experienced abuse as children and/or victimization while homeless. These experiences increase the likelihood of developing trauma-related symptoms and posttraumatic stress disorder (PTSD). Few studies have, however, examined correlates of trauma and PTSD to identify targets for prevention and intervention. We used multinomial logistic regression to assess whether child abuse, victimization once homeless, features of homelessness (duration and transience), and personal resilience (self-efficacy and social connectedness) were associated with trauma and PTSD among 600 homeless young adults. Compared with those who had not experienced trauma, those who had were more likely to have been physically and/or sexually abused in childhood and physically victimized once homeless. Compared with those who had not experienced trauma, those who had experienced trauma and met criteria for PTSD were more likely to have been physically and/or sexually abused in childhood and physically and/or sexually victimized once homeless, and to have lower self-efficacy and social connectedness. Attention should be paid to these correlates of trauma and PTSD in developing and refining trauma-informed prevention and intervention approaches.