Introduction: Studies regarding the use of support services for persons with a dual diagnosis of intellectual disability and psychopathology are scarce; even fewer have focused on children and young adults. The aim of the present study, conducted in Israel, was to compare the use of support services and their perceived effectiveness by families of children and young adults with intellectual disability (ID) and with dual diagnosis. Methods: Data were collected from 195 family (parental) caregivers of individuals with ID or dual diagnosis, aged 10-30. Using a structured questionnaire, family caregivers reported on the use of support services and on their perceived effectiveness. Results: Findings showed that in addition to the obvious mental health services, caregivers of individuals with ID and dual diagnosis report using a range of services and resources. Caregivers of persons diagnosed only with ID perceived some of the mental health services as being more effective than did caregivers of individuals with dual diagnosis. Conclusion: We advocate for enhanced training for professionals working with individuals with dual diagnosis within all services. Furthermore, parents need to be supported in their search for services for their child and in dealing with complex situations. In addition, more research is needed to identify why individuals with dual diagnosis may not benefit from current mental health services and, in line with this, develop more effective services. Finally, we advocate for the establishment of a one-stop shop that can provide for the comprehensive needs of these individuals within one center.