Mature epistemic beliefs underlie higher-order thinking and learning outcomes. Previous studies have established that epistemic beliefs predict task-specific performance. However, there is mixed evidence regarding the relationships between such beliefs and course-level academic performance. This study investigated whether disciplinary type ('soft' versus 'hard') could account for the mixed findings. A survey was conducted among 1366 Indonesian university students enrolled in 'soft' (design, psychology and law) and 'hard' (engineering, biotechnology and pharmacy) disciplines. Beliefs about the uncertainty of knowledge, the subjectivity of knowledge and authority justification were measured before the start of semester. Findings indicated that, while subjectivity belief was not associated with grade point average in the soft disciplines, it negatively predicted it in the hard disciplines. Meanwhile, uncertainty belief, but not authority belief, was positively associated with grade point average in both disciplines. Hence, the relations between some epistemic beliefs and academic performance may depend on the nature of the discipline.