Many American college students lack the academic skills to be successful. College faculty members struggle to help these disadvantaged students excel in a college environment. There is a need for identified strategies to help college students develop academic skills such as critical thinking. The purpose of this study was to determine if participation in the high-impact practices of undergraduate research, learning communities, capstones, internships or study abroad is a strategy that can be utilized by college faculty members to teach critical thinking skills to academically disadvantaged college students. This quantitative study used a quasi-experimental within subjects pretest-posttest design. The critical thinking levels of students before participation in undergraduate research, learning communities, capstones, internships or study abroad were compared with the critical thinking levels of those same students after participation in the high-impact practices. In addition, the effect of participation in multiple practices was investigated and a comparison was made between the posttest critical thinking levels of academically advantaged and disadvantaged students. Participants were nineteen undergraduate students at a small Midwestern liberal arts university. A significant difference in pretest and posttest critical thinking scores was determined (t(18) = -2.29, p = 0.034). There was not a significant difference between critical thinking levels of students who had participated in multiple high-impact practices and those who had only participated in one high-impact practice. In addition, there was not a significant difference between the posttest critical thinking scores of disadvantaged and advantaged students. The findings from this study indicate that the high-impact practices of undergraduate research, study abroad, learning communities, capstones, and internships could be used by college faculty members to encourage the development of critical thinking in college students. Although the other differences examined were not significant, the increases in the mean critical thinking scores for students participating in multiple practices suggest that further research is needed. The change in critical thinking between advantaged and disadvantaged students' posttest critical thinking was not significant but the larger difference for disadvantaged students does indicate that further research with a larger sample is needed. [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.]