One of the categories of failing public schools is turnaround schools, which requires effective school leadership and teachers to improve student achievement scores. However, the impact of principals' self-efficacy beliefs in successfully turning around failing schools is unknown. The purpose of this research was to investigate principal self-efficacy in turnaround schools to determine to what degree principal self-efficacy beliefs influences student achievement in English Language Arts and mathematics. This study was based on a self-efficacy theory that was derived from Bandura's (1986) social cognitive theory. Social cognitive theory, originally theorized as the Social learning theory in the 1960s, was expanded to explain how people learn from social interactions and reciprocal interactions of behaviors, people, and their environments. This study followed a quantitative correlational research design in which cross-sectional surveys were distributed to a purposive sample of principals in one public Florida school district with a history of successfully turning around failing schools, then followed by Independent t-tests and correlation analyses. The Principal Sense of Efficacy Scale was used to collect data on principal self-efficacy beliefs and then analyzed for significant correlations. Findings indicated that instructional leadership had the highest means scores, suggesting principal felt the most comfortable with making a positive impact on the learning in their school. Furthermore, gender and race/ethnicity differences in principal self-efficacy beliefs exist, but not for age. Years of experience as a turnaround principal seemed to have some influence, but they did not significantly impact self-efficacy beliefs in instructional leadership, school management, or moral leadership. However, further research with larger, more diverse samples is needed before these findings can be generalized. Furthermore, no statistically significant correlations existed between self-efficacy beliefs and English Language Arts and math achievement scores. While these findings provide insights into the relationships between principal self-efficacy beliefs, demographic factors, and student outcomes, they also underscore the complexity of educational outcomes and the potential influence of multiple variables. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]