We view the school principal as a school-wide community organizer who is central in actuating collective teacher efficacy. The purpose of the present study was to explore the attitudes, practices, and behaviors of principals who develop collective teacher efficacy. Data were gathered through semi-structured interviews of 24 principals. The data from each interview were analyzed through content analysis and then examined in relation to all other interviews in a cross-case analysis. The results presented common attitudes, practices, and behaviors of principals developing collective teacher efficacy through facilitative leadership that consists of supportive relationships, scaffolded collaboration, and advancing expertise. The insights gained from this study may help school principals shape their own practices relative to collective teacher efficacy. Additionally, finergrained analysis revealed social and academic factors similar to those that have been associated with Collective Classroom Efficacy.