Many students in Grades 9-10 are not meeting state standards on standardized mathematics tests in the Southeastern United States. The focus of this study was to determine if a teacher's confidence level affects student success in mathematics and to discover which type of teacher self-efficacy best predicts student performance. Bandura's social cognitive theory served as the theoretical foundation for the study. The research question involved understanding the relationship between teacher self-efficacy and student achievement in high school mathematics. A quantitative correlational, cross-sectional survey design was employed. Data were collected using the Teachers' Sense of Efficacy Scale (consisting of a number of subscales reflecting different aspects of self-efficacy), student end of course test data, and a teacher questionnaire that assessed sociodemographic information. Multiple regression analysis was used to determine which combination of variables could best predict student achievement. Results indicated that teacher efficacy significantly predicted student achievement, with the best combination of predictor variables being the subcategories of teacher efficacy in student engagement and teacher efficacy in classroom management combined with teacher age and experience. Implications for social change include improved student mathematics achievement and potentially an increase in student graduation rates. [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.]