The main aim of this article is to describe the development of a new day treatment program for older children (8-11 years) with behavioural problems. The article outlines the content of the program and it also sets out the rationale behind the development of the new day service. The day program involves therapeutic and educational input and children attend the program two days a week for one academic term (10-13 weeks). Therapeutic input focuses on improving functioning in relation to a number of developmental processes that are known to be linked to the development of problem behaviour. These include improving emotional competence, dealing with peer relationship problems and interpersonal difficulties, and changing negative patterns of thinking about the self and others. The GoZone team also attempt to work collaboratively with the children's families and schools. A preliminary investigation of the effectiveness of the program is also reported. Parents and teachers completed the Strengths and Difficulties Questionnaire (SDQ) pre- and posttreatment. Findings showed that over the course of treatment parents reported a significant decrease in overall levels of emotional and behavioural problems and also reported a significant decrease in levels of emotional symptoms and peer problems. However, no significant changes in emotional and behavioural functioning were reported by teachers at school over the course of treatment. Potential ways of boosting the magnitude of positive change achieved by the new day treatment program are discussed.