Universities and colleges are consistently being held accountable for measurable outcomes from internal and external stakeholders. Outcomes such as the development of critical thinking skills have been tied to funding from state and federal governments and employers believe that graduates should be able to think critically and produce results immediately upon being hired. Although there has been extensive literature on the outcomes from academics and faculty-led portion of students' time on campus, research on developing critical thinking skills from co-curricular activities is less prevalent. The purpose of the study was to examine the link between involvement in co-curricular activities and the development of critical thinking skills. The correlational study took place at a private religious university in North Central Texas. The non-probability sample consisted of 173 freshman and senior students who responded to the 2016 National Survey of Student Engagement (NSSE). Due to the non-experimental nature of the study, no causal inferences were drawn. There were 24 items on the NSSE that measured Co-curricular activities of Discussion with Diverse Others, High Impact Practices, Quality of Interactions, and Supportive Environment. Critical thinking skills of Reflective and Integrative Thinking, Higher Order Learning, and Quantitative Reasoning were measured by 15 items. Based on the analysis of the data, the researcher concluded that there is a relationship between co-curricular activities and development of critical thinking skills. Supportive Environment was most likely to influence the development of critical thinking skills for all students who participated in the NSSE. The study provides university administrators, faculty, and staff with a better understanding of how co-curricular activities can lead to the development of critical thinking skills that can be instrumental in developing and conducting outcome-oriented programs. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]