A label can convey nonobvious information about category membership. Three studies show that preschoolers (N=144) sometimes ignore or reject labels that conflict with appearance, particularly when they are uncertain that the speaker meant to use those labels. In Study 1, 4-year-olds were more reluctant than 3-year-olds to accept that, for example, a cat-like animal was a dog just on the basis of hearing it called a dog. In Studies 2 and 3, this reluctance was overcome when the speaker explicitly or implicitly indicated that use of the unexpected labels was intentional. These studies demonstrate that preschoolers do not treat labels as atheoretical features of objects; rather, they interpret them in light of their understanding of the labeler's communicative intent.