Background: Research about learning in youth activism has generated important findings about how young people learn to critique inequality and exercise collective agency. This emerging line of research, however, has been limited by its geographic focus in North America, a tendency to assume single bounded groups as sites of learning, and limited engagement with theories of power and social change. Methods: We draw on data from a three-year ethnography of a South African youth-led organizing group, Equal Education (EE), which successfully pressured the national government to adopt an education bill that it had previously resisted. Our inquiry is guided by a broad question: how did EE members learn to build power in this contentious sociopolitical context? Findings: Facilitation and apprenticeship by more experienced near peers in EE supported young people's understanding of inequality and their participation in nonviolent political activism. When stepping into a contentious public sphere, young people learned how to build political relationships with trade unions and community elders in order to claim power and influence political change. Contribution: This study adds to literature on learning in youth activism by showing how young people learn how to navigate contentious politics and exercise political power through multigenerational alliances.