OBJECTIVE: This project has 2 aims: First, to identify and summarize the most clinically important aspects of the published evidence on physical activity and sport in children and young people for the treatment or prevention of depression, anxiety, or symptoms of these conditions. Second, this study aims to funnel and develop this evidence to create clinically meaningful summaries on the Moving Medicine website and to guide clinicians on the day-to-day conversations clinicians have with children and young people about the benefits of physical activity for mental health. DESIGN: This mixed methods study combines a scoping review with expert clinical review using the knowledge creation funnel component of the KTA framework. DATA SOURCES: We searched Pubmed, OvidSp, Cochrane, OvidEmbase, OvidEmcare and AMED databases using the following search strategy, which included appropriate truncation symbols to account for variations of the search terms and maximize searches: Depression OR depressed OR anxiety OR "generalised anxiety disorder" OR anxious* OR "low mood" OR "Mood disorder" AND Children OR Child OR adolescen* OR teenager OR "young people*" OR "young person*" AND Exercise OR "physical activ*" OR sport OR "Physically activ*". RESULTS: Sixty-eight studies were included in this review, and evidence suggested that interventions of varying intensity can reduce symptoms of depression and anxiety in children and young people. The effects of physical activity on other mental health outcomes were also encouraging. The available evidence suggests that physical activity is a promising strategy to improve mental health in children and young people. CONCLUSIONS: The literature overwhelmingly supports the benefits of regular physical activity both in the prevention of mental health issues for children and young people and in reduction of symptoms for those with already established symptoms. This review has translated this knowledge into accessible and relevant resources for healthcare professionals to use in their practice.