<p>In this paper I argue that many metaethicists commit a fallacy that has not yet received a clear and unified description. I develop a characterization of this “transparency fallacy” by illustrations drawn from the metaethical writings of both historical and contemporary figures. The basic idea is that metaethicists often illicitly assume that if some fact about our moral thought and talk is true, then this fact is transparent to competent moral speakers, in (roughly) the sense that they believe it. In particular, I show that metaethicists often implicitly assume that the meanings, referents, truthmakers, attitude-types, and psychological roles of moral terms or judgments are transparent to competent speakers.</p>