Young children under 6 years old are over-represented in the U.S. child welfare system (CWS). Due to their exposure to early deprivation and trauma, they are also highly vulnerable to developmental problems, including language delays. High quality early care and education (ECE) programs (e.g. preschool, Head Start) can improve children's development and so policymakers have begun calling for increased enrollment of CWS-supervised children in these programs. However, it is not a given that ECE will benefit all children who experience maltreatment. Some types of maltreatment may result in trauma-related learning and behavior challenges or developmental deficits that cause children to respond to ECE settings differently. The current study uses data from a nationally representative survey of children in the U.S. child welfare system, the National Survey of Child and Adolescent Well-Being II, to assess whether young CWS-supervised children (N = 1,652) who were enrolled in ECE had better language development outcomes 18 months later than those not enrolled in ECE. We also explore whether the type of maltreatment that brought children to the CWS' attention moderates the relationship between ECE and children's language development. After controlling for children's initial scores on the Preschool Language Scale (PLS-3), type(s) of maltreatment experienced, and child and caregiver demographics, we found that ECE participation predicted better PLS-3 scores at follow-up, with a positive interaction between ECE participation and supervisory neglect. ECE seems to be beneficial for CWS-involved children's early language development, especially for children referred to the CWS because they lack appropriate parent supervision at home. (author abstract)