The climate crisis represents one of the most pressing challenges of the twenty-first century, demanding urgent and transformative action at every level of society. However, traditional climate governance structures have long been dominated by established political and economic institutions that often prioritize short-term interests over long-term planetary health. In recent years, a powerful force has emerged to challenge this status young people and youth-led climate movements. Beginning notably with Swedish activist Greta Thunberg's individual school strike in 2018, a global wave of youth activism has fundamentally altered the climate change discourse, compelling world leaders to confront the urgency of climate action while simultaneously demanding a meaningful voice in the policymaking processes that will determine their futures. This research paper examines the multifaceted role of youth activism in climate policymaking, analyzing how young people have transcended symbolic participation to become influential agents of change within international and domestic climate governance. Through examining key movements, mechanisms of influence, and the evolving institutional recognition of youth voices, this paper demonstrates that youth activism has not merely raised awareness about climate change but has catalyzed substantive policy shifts and institutional reforms that prioritize intergenerational equity and climate justice.