The purpose of this study was to examine the relationship between grit, mathematics self-efficacy, students' career interest in STEM, and student achievement in Algebra I. The study was intentional in examining the concepts of self-efficacy, achievement, and career interest as part of STEM education research. The research was completed during the fall in 2019 with 118 seventh and eighth grade Algebra I students within a large suburban district located in southeast Texas. Students participated in quantitative data collection with the Short Grit Scale, the S-STEM, and individual interviews. All 118 students completed the survey and 11 students participated with individual interviews. Pearson's Product-Moment correlation (r), structural equation modeling (SEM), and thematic coding were used to analyze the data collected. [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.]