The study examines the correlation between collective innovativeness of the teaching staff and the principal's leadership style as well as additional school structure characteristics. The construct of collective innovativeness is examined as a precondition of successful school improvement processes driven by the teaching staff. Based on theoretical interdisciplinary analyses and empirical findings, the examined hypothesis was that the principal's leadership directly and positively influences the collective innovativeness of the teaching staff. The results of the structural equation modeling (partial least squares regression) indicate that the principal's leadership style is the strongest predictor of teachers' collective innovativeness and, together with the teaching staff's perception of hierarchical structures and autonomy within the school, explained 51% of variance in the construct. The paper highlights important aspects of principals' leadership styles that can encourage collective innovativeness among teachers.