Research Findings: School readiness is a strong predictor of adjustment in elementary school and beyond. Children in foster care are at particular risk for academic and social difficulties in school. Limitations in self-regulatory skills and caregiver involvement among these children might contribute to a lack of school readiness. This study presents the immediate effects on school readiness of a targeted, short-term intervention designed to improve children's early literacy, prosocial, and self-regulatory skills during the summer before kindergarten entry: Kids in Transition to School. Using a randomized controlled trial design, we assigned 192 children in foster care to either an intervention or services as usual comparison condition. Multimethod, multi-informant assessments were conducted immediately prior to and following the completion of the intervention. The results from structural equation modeling indicated that the intervention had significant positive effects on early literacy and self-regulatory skills. Practice or Policy: An efficacious, short-term, readily scalable, theoretically based intervention targeted at specific vulnerabilities for children in foster care may help to improve the school readiness and eventual school adjustment of these children. (author abstract)