As the pressing problems of the real world are not organized into disciplinary categories, there is an urgent need to make doctoral education more interdisciplinary. As an extension of the border-crossing metaphor that is commonly used for interdisciplinarity, academic educators wishing to engage students in this activity might consider themselves as guides on an arduous journey. In this critical reflection, the author will justify why interdisciplinarity is needed, propose strategies for enabling it at the doctoral level, and comment on how such efforts will bring the doctorate up to date with the practical needs of the current century. His context is the curriculum of an interdisciplinary graduate programme situated in Singapore, where a typical class consists of students from various STEM disciplines. He reflects on his own efforts to devise strategies for promoting interdisciplinarity amongst his students, based on the pedagogical literature on interdisciplinary learning and his own interdisciplinary research.