Nationally, collective teacher efficacy (CTE) has been correlated with higher levels of student achievement. The problem addressed through this study was that local school district leaders have been unsuccessful in cultivating CTE through the district's collaborative planning process. Guided by the enabling conditions of CTE, the purpose of this basic qualitative study was to explore how local middle school principals cultivated CTE in their schools through the collaborative planning process. Eight middle school principals with experience using the district's collaborative planning process completed semi-structured interviews. Data analysis employed inductive, open coding to identify themes. Themes indicated that, as part of the collaborative planning process, the middle school principals showed deference to and trust in teachers' knowledge and ability, empowered formal and informal teacher leadership, acknowledged teacher accomplishments, used collaborative planning as job-embedded professional learning, employed different schedules to promote collaborative planning success, and were open to teacher feedback. Findings suggest that, despite their knowledge of CTE and use of the collaborative planning process, middle school principals needed a deeper understanding of how to cultivate CTE. A position paper was developed for school district leaders to suggest solutions for improving the quality of principals' leadership relative to use of collaborative planning and fostering CTE. With enhanced use of the collaborative planning process, district leaders will be better positioned to create positive social change within schools by creating an educational environment that effectively cultivates CTE which may then lead to improving student achievement over time. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]