Despite rapid job growth in the United States (U.S.) within the fields of science, technology, engineering, and math (STEM), historically at-risk students such as women, minorities, and first-generation college students remain underrepresented in STEM majors. As such, colleges and universities have begun developing STEM-specific interventions and retention programs to facilitate their success in STEM majors. The purpose of this study was to explore whether participation in a STEM-specific intervention had a meaningful effect on various academic outcomes for historically at-risk undergraduate students enrolled in STEM courses at a regional university in Southeast Texas. Using a quantitative, non-experimental secondary data analysis of archival at-risk student data (N = 101), independent samples t-test and the Mann-Whitney test were used to investigate if the intervention had an effect on student achievement, retention, and matriculation. Findings suggested the intervention had a main effect on student achievement, but not on STEM retention or graduation rate. Implications for practice and recommendations for future research are included. [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.]