This paper elaborates on school leaders’ strategies in efforts to change school culture and teachers’ professional norms. The point of departure is the opportunities and obstacles that emerged in a large-scale program (with over thirty participating schools in twelve different municipalities) for the implementation of inclusive learning environments. The paper has an organisation-cultural theoretical approach, focusing on how to change teachers’ practices through the change of school culture and teachers’ professional norms. The empirical data has been collected through several recurrent interviews with principals at school levels (in as many as 31 schools), as well as coordinators and executives at the administrative levels (in 12 different municipalities). The results stress the importance of a shared and delegated leadership between different levels and units. Successful implementation rests on the participation of many, the possibilities to influence the processes, and shared responsibility between school leaders, educators – and pupils. As the study shows, this is not progressions or practices that can be forced through binding rules or new formulations in policy documents. The change in professional norms – a prerequisite for changes in pedagogical practises enabling inclusion – must grow from below, using the impetus, inspiration and legitimacy from the levels of principals, but where renewed practice should find its forms through a shared, delegated and collegial leadership.