Decisions about how mathematics is communicated--and who gets to communicate that work--influence who has "mathematical authority" in a classroom. But what exactly does that mean, and in what ways can that authority be shared between students and their teacher? In this article, the authors expand on the idea of what it means to have authority in mathematics classrooms and consider different ways teachers can: (1) support students to take on more mathematical authority; and (2) purposefully leverage their mathematical authority to create a more productive learning environment for them. This expansion also includes looking beyond the authorship of mathematical ideas when thinking about how authority is distributed in a classroom to include authority for representing and speaking, two ubiquitous forms of communicating mathematics.