Sanger Unified School District in California's Central Valley had been named one of the worst 98 school districts in California. It was not only one of the worst-performing districts in a state with 1,042 districts, but it also had been flagged as one of the first to be named a program improvement district under No Child Left Behind. In this article, the author describes what he discovered about the workings of an effective professional learning community. The district had been one of the state's worst on academic measures but now serves as a model for others.