In education teachers' individual and collective efforts are essential in order to improve student learning and realize reforms successfully. In this respect, capacity development is very important at schools. Capacity development is a complicated state based on motivation, skill development, learning, positive organizational culture and support mechanisms. It is believed that establishing professional learning communities develops capacity and improves students' learning at school. In order to develop capacity and maintain it, establishing "professional learning communities" at school is one of the administrative roles that school principals should fulfil. As far as capacity development is concerned, it is more important for school principals to establish collaborative professional learning communities at schools than ever. Therefore, the main purpose of this study is to present what principal roles in establishing professional earning community are in the current system. The research was conducted qualitatively and the data were collected through interviews with 15 principals. Results reveal that school principals have significant roles establishing professional learning communities. However, they do not perform this role adequately. (C) 2015 The Authors. Published by Elsevier Ltd.