Inequities and disparities of various forms exist in public schools that significantly impact the academic success and healthy development of many students. The detrimental effects of social injustices within schools are often ignored by school-based professionals (SBPs) because an entrenched intrapsychic perspective dominates the professional discourse. In this article we explain how the medical model, and its discursive articulation in the Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; American Psychiatric Association, 2000), discourages SBPs from engaging in social justice advocacy in school settings. Next, we describe the ecological paradigm necessary for assessing and treating environmental-based problems within the ecosystem of students. We then argue that ecological psychology provides SBPs with a professional discourse that frames the need for social justice advocacy and action. Finally, we provide specific ways in which SBPs can become knowledgeable and empowered advocates both with and on behalf of K-12 students and their families.