BACKGROUND: There has been increasing interest in involving the public in systematic reviews as they provide a shortcut to the evidence and arguably have greater influence over policy decisions and ultimately people's lives. Case examples of this involvement are rare, especially for reviews focused on children and young people. This study describes the process and impact of consulting with a young people's advisory group to inform decision making in a systematic review on the effects of schools and school environment interventions on children and young people's health. METHODS: Consultations were conducted with a pre-existing group of young people brought together to advise on public health research. Their views were sought at two key stages: (i) at the beginning when general views relating to the policy problem under study were elicited; and (ii) half-way through to advise on how to focus the review on key priorities. RESULTS: Young people's involvement in our review ensured that the scope of our review was appropriate and that issues which were important to young people were considered. The group was especially valuable in terms of prioritizing in a relevant and meaningful way. A crucial additional impact of involvement was young people providing 'early signals' of key themes for the synthesis.