Background/Context: Little research has directly examined whether principal leadership can increase the degree to which teachers work together regularly in focused ways around content. Prior research has shown that reform efforts seeking to alter the process of teaching can be successful if teachers collaborate to build capacity and improve instruction. Furthermore, the research literature has highlighted supportive principal leadership as a key component of teachers' perception of an effective collaborative change process. Purpose: This study examines the empirical link between teachers' perceptions of principal support for change and teachers' reports of the degree of collaboration and communication with one another around literacy. Setting: The data for this study was collected in all 165 Reading First schools in Michigan in the 2006-2007 school year. Subjects: Survey data was collected from 1,738 teachers across all schools. Research Design: Data for this study was collected as part of the evaluation of Reading First in Michigan. Literacy teachers in kindergarten through third grade completed surveys at three points throughout the school year (fall, winter, and spring). These surveys contained questions about principal support for change and collaboration and communication around literacy. Data Collection and Analysis: The primary analytic method employed in this study was multilevel modeling. Factor analysis and full information maximum likelihood estimation were also used. Findings/Results: The measure of principal support for change was a significant positive predictor of teachers' assessment of the degree of regular collaboration and communication around reading instruction; a one standard deviation increase in teachers' reports of principal support for change was associated with a 0.202 standard deviation increase in teachers' assessment of the degree of collaboration and communication around literacy when controlling for the other variables in the model. Conclusions/Recommendations: This paper demonstrates that the degree to which teachers report collaboration and communication around literacy in Reading First schools is significantly related to their perceptions of principal support for change. If policymakers expect teachers to collaborate around issues of instruction, then they need to consider the principal's role in supporting change in the school by encouraging teachers to improve their instruction and take the risks associated with innovation. In sum, the results of this study are important for educators, as the role of the principal is potentially critical for positive changes in teacher collaboration and, consequently, student achievement in high-poverty schools.