Purpose: The purpose of this qualitative collective case study was to explore elementary principals' perceptions of the development of trust and its influence on teacher and collective efficacy in one suburban unified school district. This study examined what leaders said they did to build trust with all stakeholders at their elementary school sites and explored how leaders perceived their ability to influence teacher efficacy and collective efficacy. Methodology: Interviews with elementary principals provided insight and personal perspective as it related to trust and efficacy. Findings: Findings described the value of accessibility to teachers, reliability, and openness with information to develop trust with teachers. Building meaningful relationships, shared leadership, and open communication with individual teachers helped the elementary principals develop trust with individual teachers and influence efficacy. Conclusions: This research supports the development of leaders by identifying tangible things principals do to develop trust with teachers and influence teacher and collective efficacy. Recommendations: Further research should include principals in various districts across elementary and secondary settings. Furthermore, a mixed-method research design to determine the relationship between what principals say they do to develop trust and teachers' perception of trust between teachers and the principal would contribute to the field of study. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]