KidsMatter (KM) is an Australian national primary school mental health promotion, prevention and early intervention initiative. It uses a whole-school approach and a framework built around the four components of: Positive school community; Social emotional learning; Parenting support and education; and Early intervention for students experiencing mental health difficulties. It was recently trialed in 100 schools across Australia during 2007 and 2008. This report presents findings from the evaluation of this pilot phase, which examined the implementation, engagement, and impact aspects of the of the initiative for schools, teachers, parents, and students.