Middle school girls who are at risk have experienced a disproportionate number of intense and disruptive traumatic life events. Such events can adversely affect healthy development and often contribute to higher levels of school failure and problem behavior. Few programs focus on helping at-risk middle school girls achieve school success through gender-specific developmental intervention, and little research has examined the outcomes of such programs. This study describes the lifetime histories of trauma and developmental challenge among a sample of at-risk middle school girls and confirms Project Challenge as an effective program for helping girls recover their self-confidence and succeed in school. The quantitative portion of this mixed methods study used a true experimental design. Repeated Measures ANOVA results supported significant differences in: self-confidence, self-esteem, perceived social support, mattering, and identity. Effect size estimates suggested a strong effect on self-confidence; a stronger-than-moderate effect on self-esteem, mattering, and identity; and a moderate effect on perceived social support. Gains in self-confidence, self-esteem, and identity persisted two weeks after treatment. Qualitative interviews confirmed the study's quantitative findings. A one-year follow-up found 35 of 35 participants maintaining successful school outcomes.