This chapter discusses children’s citizenship practices in the climate change domain, and in the context of the global Fridays For Future (FFF) social movement led by children and youth. The movement emerged from grassroots activism at local, national and global levels, and has performed mass public actions by mobilising millions of people around the world within the short period of time in 2018 and 2019. Although the pandemic in the years that followed caused a major setback in children’s protest activities in public spaces, the movement prevailed and continues to strengthen deliberation across online and physical spaces on the global scale. Moreover, the FFF movement has built intersectional coalitions with other adult-led and social movements, endorsing the slogan that ‘climate justice is social justice’. The chapter argues that children’s climate citizenship activities linked to the movement such as school strikes, street protests, social media activism and child/youth-led litigation are pathways of public participation which aim to influence governance and societal attitudes in climate change matters. Acknowledging the evolving and dynamic nature of movement and a rapidly growing body of research in the topic, the chapter explores how researchers but also children and young people themselves are experiencing and perceiving their active citizenship through social movement activism for the climate, and ultimately, how it affects their rights.