Longitudinal survey data were used to examine the relationship between two types of childhood maltreatment, abuse/neglect and exposure to intimate partner violence (IPV), and two outcomes, substance use and dating violence, within the past year. Participants were youth ( N = 158, aged 16–19 at Time 3) involved with child protective services (CPS). A parallel multiple mediator model was used to test the hypothesis that trauma symptoms would mediate the relationship between both types of maltreatment and dating violence, marijuana, and alcohol use outcomes. Although both types of maltreatment were not directly associated with dating violence and substance use outcomes, the indirect effects of anxiety, anger, and dissociation on the relationship between maltreatment and substance use/dating violence were significant. Direct effects of both types of maltreatment on past year use of dating violence + alcohol use and dating violence + marijuana use were not significant, but results demonstrated a significant indirect effect for anger on the relationship between exposure to IPV and past year dating violence + marijuana use. No other indirect effects were significant. Findings highlight the negative effects of exposure to IPV and have implications for the development of prevention programming for youth transitioning out of CPS.