Collaborative family—provider teams have become an increasingly popular mechanism for creating and implementing individualized service and support plans for children and families with complex needs. In the context of children's mental health,this type of individualized service planning is most often known as wraparound, and it has become one of the primary strategies for implementing the system of care philosophy. A consensus has been reached about the values that underlie wraparound; however, less agreement exists regarding the specific techniques or procedures that translate the value base into practices at the team level. Difficulties in reaching agreement about guidelines or standards for wraparound practice are exacerbated by the lack of a theory describing how the wraparound process produces positive outcomes. This article brings together theory and research from a variety of sources in proposing a model of effectiveness for wraparound. The model specifies relationships between team practices, processes, and outcomes. The model is then used as a basis for recommending specific practices for wraparound teamwork.