The promotion of physical activity within schools and physical education (PE) has attracted growing interest in recent years. Schools have been acknowledged as the primary institution with responsibility for promoting activity in young people and more specifically, school PE has been recognized as having a key role to play. Given this, and based on previous reviews of the findings of formally evaluated interventions, this paper considers the evidence for the effectiveness of school-based physical activity interventions and highlights the key trends and a number of issues concerning their type, target population, design, implementation and content. Earlier reviews have provided comprehensive summaries of the effectiveness of physical activity interventions but they have not provided specific guidance for teachers' practice in schools. Thus, whilst it is acknowledged that the existing literature is not sufficiently extensive to provide definitive guidelines for schools, this paper considers the implications for practice and presents recommendations for future physical activity programmes, initiatives and interventions. (Contains 1 table.)