Classifier languages are spoken by a large portion of the world's population, but psychologists have only recently begun to investigate the psychological reality of classifier categories and their potential for influencing non-linguistic thought. The current work evaluates both the mental representation of classifiers and potential cognitive consequences for speakers of Mandarin Chinese. We first provide a taxonomy of 126 common classifiers and a large sample of the objects classified by each as a tool for this and future research. We then present four studies investigating potential variation in the mental representation of the classifier categories. The data provide evidence that at least three forms of mental representation need to be distinguished. Finally, we present a fifth study investigating the impact of this variation on the cognitive consequences of classifier knowledge. This study suggests that the differences identified in Experiments 1-4 have important implications for the likelihood of finding cognitive consequences. (Contains 10 tables.)