Purpose: The purpose of this paper is to improve the understanding of psychological factors that influence inquiry-based leadership. This study investigates how affective attitude, experienced social pressure, and self-efficacy relate to aspects of inquiry-based school leadership. A school leader's inquiry habit of mind, data literacy, and the extent to which he or she creates a culture of inquiry in the school are each identified as aspects of inquiry-based leadership. Design/methodology/approach: Data were collected from questionnaires completed by a sample of 79 school leaders. Findings: A significant relationship was found between self-efficacy regarding inquiry-based leadership and all aspects of inquiry-based leadership. Affective attitude toward inquiry-based leadership was significantly related to creating a culture of inquiry. There was no unique relationship between experienced social pressure and inquiry-based leadership. Practical implications: Administrators and educators of school leaders who aim to stimulate inquiry-based school leadership should not only focus on increasing the capacity of school leaders to lead their school in an inquiry-based way, but they should also focus on leaders' self-efficacy and on fostering leaders' positive attitude toward inquiry-based school leadership. Administrators and educators can, for example, give positive feedback, emphasize the added value of inquiry-based leadership, encourage working with critical friends, and stimulate collaboration with other leaders. Originality/value: This study addresses two gaps in the existing research, by focusing on inquiry-based leadership instead of data use and on psychological factors instead of knowledge and skills that are related to this type of leadership.