Mathematics Discipline-Based Education Research (Math-DBER) is an interdisciplinary research area that utilizes the fields of Mathematics, Data Science, and Education to investigate the teaching and learning of mathematics at the tertiary level. While Math-DBER is informed by more general research on learning and cognition, it is distinct in that the research questions are grounded in the priorities, knowledge, cultures, philosophies, and histories of the mathematics community. Further, by sitting at the boundary of fields, Math-DBER combines the methods of data science and education in impactful and novel ways.