Upward Bound is a federal program for first-generation and/or low-income students to develop the skills and further motivation to enroll in postsecondary education. Previous research has established that participating in Upward Bound frequently leads to increased postsecondary enrollment. However, the mechanisms through which these outcomes were obtained has yet to be established. Bandura's social cognitive theory, specifically relating to academic self-efficacy, provides a promising framework for understanding the relationship of Upward Bound participation on postsecondary enrollment. Academic self-efficacy can by strengthened in the following ways: performance accomplishments, vicarious experiences, and verbal persuasion. Consistent with social cognitive theory, the components of Upward Bound may increase students' academic self-efficacy and, in turn, improve their postsecondary outcomes. Because academic self-efficacy is a predictor of postsecondary outcomes including enrollment, academic self-efficacy is a possible mediator of the relationship between Upward Bound participation and postsecondary education enrollment. The present study investigated the relationships between Upward Bound participation, math self-efficacy, and postsecondary enrollment. Data from the National Center for Education Statistics High School Longitudinal Study of 2009 (HSLS:09) were analyzed. Participants were divided into three groups: Upward Bound participants, Upward Bound eligible (who were of first-generation and/or low-income status but did not participate in Upward Bound) and comparison peers (who were of continuing generation or higher-income status). Results indicated Upward Bound participation and math self-efficacy both accounted for a significant proportion of the variance in postsecondary education. However, the relationship between Upward Bound participation and math self-efficacy was unsupported. This indicates that math self-efficacy is not a mediator of the relationship between Upward Bound participation and postsecondary enrollment. Limitations, future directions for research, and implications for practice are 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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]