Throughout antiquity, Protagoras’ Man Measure statement has been understood predominantly as espousing an epistemological doctrine, i.e., a doctrine about the conditions of truth and knowledge. “The Ethical Life of a Fragment: Three Readings of Protagoras’ Man Measure Statement” adduces three ancient approaches to the Man Measure statement that evince an ethical outlook on the statement: the ethical relativist interpretation set out by Plato in his Theaetetus; a normative-quantitative interpretation of “measure,” found in allusions to the Man Measure statement; an axiological interpretation, featured in the biographical tradition around Protagoras and in Aristotle’s implicit polemics. The three ethical readings show the manifold ways in which an ancient source author interacts with a lost corpus author. Verbatim quotations are only one form of text reuse; paraphrases, allusions, imitations, and biographizing statements—although undertheorized in approaches to fragmentary authors—can be equally informative about early interpretations of Protagoras’ Man Measure statement.