This Element explores the evolutionary role of small groups as key actors in shaping human adaptability, resilience, and societal development. Drawing on cultural evolutionary theory and interdisciplinary scholarship, it illuminates the world-making and transformative capacities of small groups as primary agents of cooperative communication, cultural innovation, and transmission. Through historical and contemporary case studies from Europe, Asia, Africa, and the Americas, it examines how small groups function both as catalysts for moral imagination, cooperation, and democratic renewal, and as drivers of destructive ideologies and social disintegration. The study also reassesses the relevance of evolutionary insights for addressing the major crises of the twenty-first century. By critically engaging with foundational thinkers and ongoing debates on democratic and institutional innovation, this Element offers insights for scholars, policymakers, and civic actors committed to empowering communities and countering authoritarian regression.