The growing number of interdisciplinary degree programmes offered at comprehensive research universities aim to ensure that students gain interdisciplinary understanding, defined as knowledge and skills that provide them with the means to produce cognitive enhancements that would not be possible through monodisciplinary programmes. Previous studies suggest that interdisciplinary understanding comprises six main elements: knowledge of different disciplinary paradigms, knowledge of interdisciplinarity, reflection skills, critical reflection skills, communication skills, and collaboration skills. However, empirical evidence to support this conceptualised model is lacking. The current study therefore proposes an Interdisciplinary Understanding Questionnaire (24 items) to assess this model. Its construct validity and measurement invariance were tested among 505 first-year Bachelor's students from different academic disciplines (e.g. humanities, science, social sciences). A (multigroup) confirmatory factor analysis confirmed the conceptualised model of interdisciplinary understanding, as well as measurement invariance across academic disciplines. Implications for educational practice, for instance regarding student assessment and quality assurance, are discussed.