Studies of the relationship between policy and practice typically focus on the formal policy system alone. Yet, the public policy system does not exist in isolation. A host of nonsystem actors promote, translate, and transform policy ideas as they carry them to teachers. This study draws on neoinstitutional theories of organization to investigate the role of nonsystem actors in the relationship between policy and teachers' classroom practice. A cross-case, historical design was used to investigate how teachers in two California elementary schools responded to changes in state reading policy from 1983 to 1999. The way in which teachers responded depended in part on the nature of their connections to policy messages, which varied substantially across teachers and across policy initiatives. Policy messages from nonsystem actors were more consequential for teachers' classroom practices. Teachers' connections to nonsystem actors were influenced by the interrelationship between system and nonsystem actors as policy ideas emerged, diffused, and were implemented over time. (Contains 1 figure, 15 notes and 5 tables.)