Mellow Parenting is an intensive parenting programme which has been shown to be effective in improving the psychosocial functioning of very vulnerable babies and preschool children. We used a complex interventions model to evaluate its use with school-age children with Reactive Attachment Disorder (RAD), a serious disorder of social functioning associated with maltreatment. The programme had a positive effect on mothers' mental health, but had no measurable effects on symptoms of RAD or on parent-child interaction, although the variation between families after the group suggested that some had responded more than others. Mellow Parenting is an effective programme for vulnerable families with younger children and may be a useful adjunct in the treatment of school-age children with RAD, but it cannot be considered a definite treatment for RAD in this age group. The search continues for safe and effective treatments for RAD in school-age children.