Purpose: The purpose of this paper is to identify and analyze the professional norms surrounding school development, with a special emphasis on school principals' pedagogical leadership. Design/methodology/approach: A norm perspective is used to identify possible links between legal norms, professional norms, and actions. The findings are based on answers given by 974 school principals in a web-based questionnaire. The design of the study and the findings are structured around three questions used to identify professional norms: what tasks principals prioritize as pedagogical leaders, where the external expectations on principals are derived from, and with whom school principals communicate regarding issues related to their pedagogical leadership. Findings: The most evident professional norms identified in this study are that principals should: be present and close to the teaching and learning processes; involve teachers in quality development; enhance the development of formative assessments; engage in teacher development; develop the internal organization of the school to promote learning. Originality/value: The norm perspective and the findings of this study could be used by principals, principal trainers, and researchers to reflect on pedagogical leadership in different contexts. A challenge for principals is to become aware of the professional norms that guide them, and to close the gap between their "desirable" norms and their actions. Action alternatives and professional norms become visible through discussions emanating from questions about what leaders do, how they do so and why they do what they do, which is a way to strengthen both the profession and the individual principals.