The landscape of PK-12 education is dynamic, constantly adapting to meet the needs and demands for student learning. These changes inspire curricular reforms, and such processes compound the complexity of leadership roles within PK-12 education settings. This study explored the nature and extent of transformational leadership practices and efficacy beliefs exhibited by secondary school leaders as they implement a mathematics curricular reform. In addition, the study examined the barriers of curricular reform processes as perceived by school leaders. This study employed a phenomenological methodology as participants were asked to describe their lived experiences within the context of the mathematics curricular reform. Semi-structured interviews and focus groups were used for data collection, allowing participants to share stories and examples that captured the essence of their lived experiences. The research findings suggest efficacy beliefs related to relationships and experience influence leaders' transformational leadership practices as they facilitate curricular reforms in their schools. Furthermore, these transformational leadership practices may be used to address and overcome barriers throughout the implementation of curricular reforms. [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.]