There to date exists limited research on how emotion regulation shapes students' emotional experiences and academic development in higher education. The purpose of this study was to address this gap by examining how students in STEM (Science, Technology, Engineering, Math) degree programs (N = 174) use emotion regulation strategies related to their achievement emotions, approaches to learning, and exam performance. Data was collected across four phases pertaining to a required STEM course at the beginning of the semester, while studying for a midterm exam, and within 48 h following the exam. Results suggested that while emotion regulation while studying did not predict students' emotions more than control and value appraisals, their emotion regulation specific to the exam predicted their emotions above and beyond control and value appraisals. Findings also showed cognitive reappraisal to correspond with more positive emotions, less negative emotions, more complex approaches to learning, and better exam performance. Conversely, suppression was associated with poorer exam performance. Results additionally showed that associations between cognitive reappraisal and emotions were stronger during exams than while studying. Overall, these findings indicate that how post-secondary students choose to regulate their emotions in STEM degree programs has important implications for how they feel, learn, and perform.