The current study evaluates the effectiveness of a community anger management group for individuals with dual diagnosis, a developmental disability and psychiatric disorder. Ten individuals who demonstrated difficulties in inappropriate anger expression and anger management participated. Caregivers were also encouraged to attend the group. Sessions were held over the course of 12 weeks and employed a modified cognitive-behavioural approach. Following treatment, assessments of anger disposition and control were available for nine clients and five carers. Both participants and caregivers reported a marginally significant decrease in client's anger behaviours, and a substantial improvement in client's anger regulation. Although results should be interpreted cautiously, the findings suggest that an anger management group may be an effective intervention for individuals with dual diagnosis.