This book chapter from Toward a Global Psychology: Theory, Research, Intervention, and Pedagogy shows how psychology has the potential to address system challenges (armed conflict, HIV/AIDS pandemic, etc.) at the macro-level through macro-level approaches associated with social policies and societal influence processes. It first lays the conceptual foundation and provides a critical lens for thinking about how psychology can inform our approach to macro-level problems. An examination of social policy work and mass scale psychosocial interventions as two kinds of macro-level intervention follow. For both categories, examples of psychologically informed interventions are provided, and their role, impact, and challenges are discussed.