Youth substance use and abuse in the U.S. is a critical public health issue and a risk factor for morbidity and mortality in adolescents. Examination of risk for substance use has identified that maltreatment in childhood is a relevant factor; research has indicated that youth exposed to maltreatment are more likely than their non- maltreated peers to have substance use problems. In some cases, children are removed from their homes due to maltreatment or neglect, and recent research revealed higher rates of substance use disorders in youth residing in out-of-home placements when compared to peers in the general population. Although the relation between maltreatment in childhood and subsequent substance use is recognized, pathways related to risk and protection for substance use behavior and other negative outcomes following maltreatment have yet to be fully delineated. One important factor, coping behavior, has been implicated in the relation between adverse life events and subsequent behavioral and emotional outcomes. The association between substance use and coping remains unclear; many have hypothesized that substance use may actually be an indicator of maladaptive coping. Further, significant methodological weaknesses exist in the literature investigating the link between maltreatment and substance use in youth including overuse of retrospective reports by adults about childhood maltreatment and substance use, failure of researchers to investigate the psychometric properties of their measures of substance use or maltreatment, exclusion of relevant covariates, failure to include diverse types of abuse such as neglect and psychological maltreatment, and use of small samples. Previous reviews of the literature have highlighted the need for attention to these methodological issues and more research conducted with youth enrolled in out-of-home care. To address this gap, this study will provide a comprehensive investigation into the role of maltreatment as a predictor of substance use and coping behaviors in a sample of youth in foster care. To achieve this, the proposed study will utilize a structural equation modeling framework to assess competing models of moderation: 1) a model with maltreatment predicting substance use with coping behaviors as a moderator and 2) a model with maltreatment predicting coping strategies with substance use as a moderator. Preliminary analyses will examine the measurement model of the substance use measure, as well as potential covariates of substance use in the foster sample such as child and placement characteristics. Model testing will assess overall fit of each moderation model, then Participants will be drawn from a larger, longitudinal study funded by NIH entitled Studying Pathways to Adjustment and Resilience in Kids (SPARK) and will include 150 children and adolescents aged 8 years and older who are enrolled in Jackson County foster care. Improved scientific knowledge of the complex interactions of these factors from this study will provide a more comprehensive model for investigating associations between child maltreatment, coping behaviors, and substance use in foster care youth.