The purpose of the quantitative study was threefold: (a) to examine high-ability students in and outside an honors program at a midwestern comprehensive university to determine differences in background and demographic characteristics between honors participants and nonparticipants of similar ability; (b) to determine differences in academic self-efficacy and in- and out-of-class engagement between honors participants and nonparticipants of similar ability; and (c) to examine major influences on high-ability student GPA, reported use of critical thinking skills, academic efficacy, and academic goals. Eight research questions guided the study. Astin's (1993) Input-Environment-Output (I-E-O) model was utilized for the study's conceptual framework. Statistically significant differences were found between honors students and honors-eligible nonparticipants in cumulative ACT scores, high school and college GPA, and parental education levels as well as in levels of academic efficacy, academic goals, and exposure to diverse perspectives. Regression analyses uncovered numerous meaningful predictors of GPA, reported use of critical thinking skills, academic efficacy, and academic goals on the part of high-ability students. The findings of this study provide implications for policy and practice as well as opportunities for future research related to high-ability student learning and engagement. [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.]