Purpose: This study investigated the relationship between principal leadership and variation in teachers' participation in a new literacy coaching program: Content-Focused Coaching[R] (CFC). Research design: Twenty-nine schools were randomly assigned to participate in the CFC program or to serve as a comparison. Interviews were conducted with elementary school principals and coaches, and teachers completed surveys describing their experiences with their new coach. Correlation analyses investigated the relationship between the categories of principal support and the frequency of teachers' participation in individual coaching activities. Principals' actions and beliefs were also compared across schools, with teachers' relatively high and low participation in coaching, to identify patterns in principal leadership. Findings: Principal leadership was significantly associated with the frequency with which teachers conferred with their new CFC coach and were observed by their new coach as teaching reading comprehension lessons. Principal behaviors associated with teachers' increased engagement with coaches included actively participating in the CFC program and publicly endorsing the coach as a source of literacy expertise to teachers. Principal beliefs regarding a literacy coach's role and responsibilities were associated with the frequency with which teachers opened their classrooms to the new coaches. Implications: This study provides insight into the features of principal leadership that may support coaches in engaging with teachers and gaining access to their classrooms. Observing teachers' lessons is a critical dimension of effective coaching and a difficult task for coaches to accomplish. Learning how principals can positively contribute to this process could help schools and districts make more effective use of their literacy coaching resources. (Contains 9 tables and 3 notes.)