Principles drawn from contemporary developmental-contextualism are presented as a framework for guiding the design, implementation, and evaluation of school-linked prevention programs that are consistent with an emerging body of research specifying best practices in prevention. Two school-linked preventive interventions, the Gardner Extended Services School (GESS) and Supporting Teachers Supporting Students, are described and discussed according to developmental principles. Roles of counseling psychologists in each intervention are also discussed. Implications of the theory and science of school-linked prevention and the two program examples for training of counseling psychologists are described.