The climate crisis has detrimental impacts on the mental health and wellbeing of children and young people. Psychological effects include feelings of fear, overwhelm, worry, distress, hopelessness and anger; PTSD; depression; anxiety; phobias; panic disorder; sleep disturbances; attachment disorders; learning difficulties; substance abuse; shock and trauma symptoms; adjustment problems; behavioural problems; and, suicidal thinking. First Nations' children and young people are particularly at risk due to loss of place, identity, culture, land and customs informed by kinship relationships with the Earth; while sustainable land use practices and connection to Country and community can enhance climate resilience. In Western Australia (WA), some young people engage in climate activism – including striking from school – to demand government action to address the causes of climate change, including colonisation and capitalism. Climate activism can promote resilience, particularly when children and young people can emotionally engage in the climate crisis; when mental health is systemically supported; when climate communication is transparent and comprehensive; and, when activism is informed by the knowledges and wisdoms of First Nations peoples and grounded on Country. This article is co‐authored by WA young people, Aboriginal and non‐Aboriginal academics, activists and practitioners engaged in youth, mental health and climate justice spaces. We argue for structural change to address the causes of the climate crisis, alongside enhanced evidence and approaches to appropriately support the mental health of children and young people. Furthermore, we support the call of Aboriginal peoples to ensure culturally appropriate, place‐based responses based in caring for Country.