Regulatory Fit Theory research has indicated that the presence of a regulatory fit between an individuals chronic regulatory focus orientation and induced regulatory state can increase motivation, performance, and achievement. The research in support of regulatory fit theory is immense; however, there has been little research that focuses on achievement, motivation, and/or performance among school age children in general, and even more scanty in terms of mathematics. Thus, the first goal of this study was to determine whether students in a regulatory fit condition would perform higher on a mathematics task, intrinsic math motivation scale, math effort scale, and general motivation for schoolwork scale than students in a regulatory non-fit condition. The second goal was to explore whether the relationship between regulatory fit and mathematics performance was mediated by intrinsic mathematics motivation. The third goal was to determine whether the relationship between intrinsic mathematics motivation and mathematics task performance was moderated by regulatory fit. The sample consisted of 934 high school math students from the New Jersey area. Students were split into groups where they either experienced a regulatory fit or non-fit while completing a math task. Following the task, students completed self-report measures of intrinsic math motivation, math effort, and general motivation for schoolwork. Regression analyses were used to test the effects of regulatory fit on students' motivation and math performance. The presence of a regulatory fit was not significantly correlated with performance on the math task, math effort, intrinsic math motivation, or general motivation for schoolwork scales. However, a significant relationship was found between intrinsic math motivation and math task performance. Implications and limitations of the present study, as well as future directions for research are also discussed. [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.]