Transition into middle school presents complex challenges, including exposure to a larger peer group, increased expectations for time management and self-monitoring, renegotiation of rules with parents, and pubertal changes. For children in foster care, this transition is complicated by their maltreatment histories, living situation changes, and difficulty explaining their background to peers and teachers. This vulnerability is especially pronounced for "girls" in foster care, who have often experienced sexual abuse and are at risk for associating with older antisocial males. Failures in middle school can initiate processes with cascading negative effects, including delinquency, substance abuse, mental health problems, and health-risking sexual behaviors. An intervention is described to prevent these problems along with a research design aimed at testing the intervention efficacy underlying mechanisms of change. (Contains 1 figure and 3 tables.)