Legal scholars often contend that prominent Supreme Court opinions interpret the Constitution in a manner that invalidates outliers—measures found in only a small number of states, rather than spread throughout the nation. Despite the term’s ubiquity in constitutional conversation, law professors have dedicated scant attention to exploring either its conceptual underpinnings or its conceptual borders. This paucity of scholarly attention is regrettable because the term has become enshrouded in analytical confusion, which severely diminishes its utility and instills deep misperceptions about the Supreme Court’s role in issuing outliersuppressing opinions. This Article—the first extended effort to cast a critical eye on the notion of constitutional outliers—aims to clarify understanding of the concept by dispelling three principal sources of analytical confusion. First, although scholars overwhelmingly invoke the term “outlier” as though it were a single entity, scrutinizing the Court’s outlier-suppressing opinions demonstrates that four distinct concepts are in fact huddled together under the outlier umbrella: holdouts, upstarts, backups, and throwbacks. When the Supreme Court invalidates each type of outlier, it eliminates a measure during a specific temporal moment, and conflating these moments often conceals their discrete implications for constitutional theory. Second, by identifying and disentangling these outlier variants, it becomes possible to appreciate how conventional assessments of outlier-suppressing opinions founder upon close examination. Contextualizing the Court’s outlier-suppressing opinions reveals, contrary to prevalent scholarly assumptions, that they do not invariably reject measures that the nation deems antiquated, backward, and insignificant to the constitutional order. Third, because law professors have never explicitly articulated their criteria for identifying what constitutes an outlier, the term appears in legal scholarship in inconsistent and even contradictory fashions, as outlierminded theorists disagree whether some of the Court’s most celebrated opinions even fit within the outlier rubric. In an effort to foster increased coherence with the term’s usage, this Article provides specific guidelines for distinguishing outliers from nonoutliers and identifies instances in which scholars have used the term inappositely. Bringing outliers to the very center of scholarly inquiry recasts dominant understandings of critical constitutional opinions—and the institution that issued them.