Young people worldwide are increasingly participating in a global movement for climate justice, yet to date, little research has examined how youth climate justice activists conceive of and experience activism as education. The present study used in‐depth, semi‐structured interviews with 16 US climate justice activists (aged 15–17) to address the research question: How do youth climate justice activists explain and experience the educative power of their activism? The results of reflective thematic analysis bring to light youths' dual roles as ‘learners of the movement’ and ‘climate justice educators’. As learners, youth described gaining awareness of climate justice directly from the movement, as well as learning a variety of skills (e.g., organising, communication, conflict resolution) through their activist engagement. Simultaneously, youth described their role as educators through a range of activities intended to raise awareness among adult and youth audiences, including educational workshops and trainings, school visits, teach‐ins, curriculum development, talk shows and interviews, creating digital resources, social media outreach and public protest (e.g., strikes, marches and demonstrations). Beyond spreading knowledge of climate in/justice, youth activists were also educators of action and social change processes—noting that learning about governmental institutions and political processes enabled them to exercise their democratic citizenship and equip and embolden other young people to do the same (e.g., via political advocacy trainings). The findings of the present study have implications for creating climate justice curricula that not only attend to the scientific and technological dimensions of the climate crisis, but also enable learners' justice‐driven action and democratic participation.