SummaryIn recent decades there has been much interest in using cognitive–behavioural therapy (CBT) with children, young people and families. CBT is a collaborative approach, based on shared building of a hypothesis (the formulation) about causative and maintaining factors. When working with children, young people, their families and wider systems (e.g. a support network), therapy should incorporate interpersonal, family and systemic factors, together with developmental and attachment issues and phenomena more commonly expressed through other psychotherapeutic modalities. There is growing clinical experience that systemic cognitive–behavioural formulation can lead to systemic-process working on an individual, parent–child, family or wider-system basis. Formal evaluation of this approach is needed to consider where it fits among established psychotherapies in mental health work with young people and their families.