The field of mathematics education research has seen a resurgence of interest in understanding collaborative learning because students in K-12 classrooms are increasingly expected to make sense of mathematics problems together. This Research Commentary argues for the importance of understanding student authority relations in collaborative mathematics classrooms. How intellectual authority becomes constructed, organized, and distributed among students has implications for both mathematics learning and the development of mathematics-linked identities. This research commentary suggests directions for future work to gain clarity on the mechanisms that undergird the distribution of authority in order to support powerful mathematics classrooms.