Abstract
<title>Abstract</title> <p> Background Students' interest in their academic subject is a key determinant of motivation to learn and academic achievement. However, limited evidence exists on whether the determinants of academic performance differ between students who study their preferred subject and those who do not, particularly within higher education institutions. Objective This study investigated the determinants of academic performance among undergraduate science students in Bangladesh by comparing students with and without an interest in their study subject. Methods A cross-sectional survey was conducted among 1,910 final-year undergraduate science students from 57 departments across 20 public universities using a multistage sampling design. Academic performance was measured by cumulative grade point average (CGPA), and subject interest was assessed using a binary self-reported measure. Separate three-level multilevel regression models were fitted for students with and without subject interest. Results Students studying their preferred subject achieved significantly higher CGPAs than those without subject interest (t = 10.25, <italic>p</italic> < 0.001; Cohen's <italic>d</italic> = 0.51). Institutional clustering explained 13.2% and 17.6% of the total variance in academic performance among students with and without subject interest, respectively. Among interested students, academic performance was primarily associated with individual characteristics, including academic satisfaction, class attendance, scholarship receipt, regular study habits, maternal education, and gender. In contrast, students without subject interest benefited more from effective classroom teaching, assignment-based learning, access to PhD-qualified teachers, and high-quality assessment. Extracurricular facilities, student accommodation, and transportation services were positively associated with CGPA. Conclusions Academic performance is shaped by different individual and university-level determinants depending on students' subject interests. These findings underscore the importance of tailored educational policies and supportive learning environments to enhance academic success. </p>