In response to the current demands and trends within education, the disciplines as one of the core long-standing organizing structures within knowledge production and transmission are questioning and shifting what and how they teach. Universities are increasingly offering interdisciplinary subjects and programmes as an alternative to or alongside disciplinary subjects. This paper investigates the underlying themes and principles that inform curriculum debate around the value of the disciplines and interdisciplinarity in Australia when compared to the views and practices of academics. A focus on the knowledge that is included in discipline-based and interdisciplinary curricula reveals interdisciplinary knowledge to be more weakly classified and framed than discipline-based knowledge. This has consequences for the depth of interdisciplinary knowledge and requires the consideration of the structure and place of interdisciplinary curricula in university education.