A description and test of the Holistic Student Assessment Tool (HSA), an assessment tool to measure children’s and adolescents’ resiliencies in relation to externalizingand internalizing problem behaviors. The HSA is based on the authors’ research-based clinical-developmental Clover Leaf Model of resilience and psychopathology, and is one of the first attempts at closing the gap between risk and resilience approaches in developmental assessment. The HSA was tested in a cross-sectional sample of 423 children and adolescents.The results lend support to the HSA as a valid measure of children’s and adolescents’ resiliencies. Furthermore, the resilience scales mostly exhibited the theoreticallyexpected convergent and divergent relationships with the psychopathology scales. In addition, we show how the resilience scales predict adolescents’ externalizing and internalizing symptoms. We contend that evidence-based intervention to address youth aggression needs to be based on sound developmental assessment.