School leaders’ actions have become an important aspect of research into schools’ ability to create high-quality learning and teaching. As expectations of school leaders are high and large resources are invested in principals’ education, there is a need to study the effects of these educational initiatives. In this article, we report on longitudinal research studying the national training programme for principals in Sweden. The emperical data is based on individual semi-structured interviews with principals, teachers and students at four Swedish schools. The aim is to examine various aspects of the programme’s impacts on both school organisations and principals’ leadership in practice. Using Giddens’ theory of structuration (Giddens, 1984), we focus on the common meaning making—the so-called structuration process—in the participating schools. Structures are not; rather, they are created and recreated in a process constantly influenced by the agents. Furthermore they are manifested in rules and routines that can be understood as invisible, underlying codes that arise in everyday interactions and are expressed in actions. Giddens’ theory of structuration enabled us to identify prominent changes that occurred in the participating schools during the study. Our research questions are as follows:1.     How does the structuration process emerge based on principals’, teachers’ and students’ views on the rules and routines that constitute the local school?2.     What connections are to be found between principals’ participation in the programme and how they perform as leaders in the structuration process in their local school?