Purpose: The purpose of this study was to investigate the extent to which the relationship between (a) student demographic variables (i.e., ethnicity, gender, first generation status, low income), college admission variables (i.e., admission status, SAT/ACT scores, remediation requirements), and (b) GPA and retention was influenced by first-year seminar (FYS) course participation at one Tier II doctoral university in the southwestern United States. Method: To examine differences among students who took the FYS and students who did not take the FYS among specific student variable groups an explanatory, quantitative, non-experimental, cross-sectional research study was conducted. Institutional data for the entering first-time first-year class of 2014 at one 4-year university were examined. Six research questions were constructed to examine the differences in GPA outcomes and FYS course participation by student variable group using six separate two-way ANOVAs. In cases where data were non-normal, a Kruskal-Wallis was presented for comparison. If there was heterogeneity of variance, a Welch test was presented for comparison. Six additional research questions were constructed to examine the differences in one-year retention and FYS course participation using a chi-squared statistical test of independence. Findings: For ANOVA results that compared GPA outcomes and the statistical interactions with the FYS course, several student groups had statistically significantly higher GPAs when compared to their peers in the same student group who did not take the FYS course: Black, Hispanic, at-risk (development education), first-generation, and low-income (Pell Grant recipients). For chi-squared statistical results comparing student variables and one-year retention outcomes, male students, students reporting as not first-generation status, and students who did not receive the Pell Grant (low-income status) had statistically significantly higher retention rates if they took the FYS course. Although statistical significant was present within several variable groups who took the FYS, small effect sizes were also present in each finding indicating negligible practical significance. Implications for practitioners and researchers are discussed in the context of Tinto's (1975) theory of student departure and Astin's (1984) theory of student development theory. [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.]