Raising cancer awareness among adolescents has potential to increase their knowledge and confidence in identifying cancer symptoms and seeking timely medical help in adolescence and adulthood. Detecting cancer at an early stage is important because it reduces the risk of dying of some cancers and thereby contributes to improved cancer survival. Adolescents may also play an important role in increasing cancer communication within families. However, there are no randomised controlled trials (RCT) of the effectiveness of school-based educational interventions to increase adolescents’ cancer awareness, and little is known about the role of adolescents in the upward diffusion of cancer knowledge to parents/carers. The aim of this study is to determine the effectiveness of a school-based educational intervention to raise adolescent and parent cancer awareness and adolescent-parent cancer communication.