This article explores how contemporary developmental psychology, specifically developmental-contextualism, provides a conceptual framework for practice and research by counseling psychologists who work with schools. Developmental-contextualism articulates how human development (a) is affected by context, (b) involves bio-psycho-social levels, (c) occurs during the life span, and (d) includes strengths and deficits. The authors delineate how these four developmental principles, in conjunction with the traditional strengths of counseling psychology, can guide the application of effective interventions with school-aged children and their families.