Children in contact with the child welfare system (CWS) represent a vulnerable population that is at an increased risk of poor mental health and academic outcomes. Although the majority of research has focused on the academic benefits of school engagement, studies have also found a negative association between school engagement and youth mental health outcomes. Surprisingly limited research, however, has considered the possibility of a bidirectional relationship between school engagement and youth mental health, and even fewer studies have examined this relationship in high-risk populations, such as children in contact with the CWS. The present study addresses this issue by utilizing longitudinal data from a national sample of 2633 children in contact with the CWS, the National Survey of Child and Adolescent Well-Being (NSCAW I), to examine the possible bidirectional relationship between school engagement and mental health symptoms. Data were collected from this sample (mean age = 10.04; 52.3% female) over three time points (18 months apart). Structural equation modeling results indicated that students' mental health (externalizing/internalizing symptoms) predicted subsequent school engagement levels. School engagement, on the other hand, was not a predictor of mental health symptoms at later time points. Findings point to the existence of a unidirectional relationship from mental health symptoms to school engagement for children in contact with the CWS. Directions for future mental health interventions for this population are discussed.