In this article, the author argues that urban school reform falters, in part, because of the lack of an organized political constituency among the stakeholders with the most direct interest in school improvement, that is, parents whose children attend urban schools. The author examines community organizing as a potential strategy to build such a constituency. Drawing primarily on extensive fieldwork research, he constructs a case study of one of the country's largest community organizing networks, the Texas Industrial Areas Foundation (IAF). He analyzes the network's Alliance Schools initiative to promote school reform in 120 public schools in districts across the state. This article finds that organizing efforts like the IAF, despite important limitations, are beginning to create an external force for change in district policy as well as to collaborate internally with educators to produce change in the practice of education within schools. (Contains 15 notes.)