This study examines students' perceptions of self-interest-based discipline choice and its effect on educational excellence in tertiary education. The main objective was to analyze the effect of self-interest-based discipline selection on educational excellence at the BS level program. A mixed-method approach was adopted. A phenomenological design was applied for the qualitative part while a survey research design was utilized for the quantitative part. The target population consisted of BS (7th & 8th semesters) students from 10 higher education institutions (HEIs) in Khyber Pakhtunkhwa. Word Cloud and Thematic Analysis were used for qualitative data analysis, while Pearson (r) and Linear Regression were applied as inferential statistics for the quantitative part. The findings reveal a moderate positive association between self-interest-based discipline selection and academic success. Recommendations include encouraging learners to choose discipline aligned with their self-interest instead of relying on others. Parents, teachers, and other stakeholders should respect learners' interests.