As with any institutional feature, the size of the Supreme Court should be informed by a definition of functional goals. This article describes how the current size of the Supreme Court is largely untethered from any such definition, and it begins the process of understanding how size and Court performance might interact. To do so, it identifies a list of institutional goals for the Supreme Court and explores how changing the size of the Court promotes or obstructs the attainment of those goals. Given that the Court's institutional goals are numerous and occasionally in tension, there is no definitive answer to the question of how large the Court should be. Instead, the optimal size of the Court depends on how one views the relative importance of each institutional goal and how those goals should be balanced. Unfortunately, the current size of the Supreme Court is not attributable to a careful balancing of these institutional goals, but instead is due to political efforts to secure power on the Court. Consequently, a reconsideration of the Court's size in light of institutional considerations is long overdue.