Cantonese shape classifiers encode perceptual information that is characteristic of their associated nouns, although certain nouns are exceptional. For example, the classifier "tiu" occurs primarily with nouns for long-narrow-flexible objects (e.g., scarves, snakes, and ropes) and also occurs with the noun for a (short, rigid) key. In 3 experiments, we explored how the semantic information encoded in shape classifiers influences language comprehension. When judging the fit between classifiers and depicted objects in an explicit ranking task, Cantonese speakers evaluated classifier-noun pairings solely in terms of grammatical well-formedness and showed no separate sensitivity to the shape features of objects. In an eye-tracking task (Experiment 2), we also found little sensitivity to shape classifier semantics during real-time comprehension. However, in a subsequent experiment in which referent objects lacked the prototypical features for their accompanying classifiers (Experiment 3), an influence of shape semantics was found in participants' incidental fixations to nontarget objects. We conclude that shape classifiers influence referential interpretation primarily through their grammatical constraints, consistent with the agreementlike nature of classifiers in general. The role of shape classifiers' semantics on processing is apparent only in specific circumstances. (Contains 6 figures, 3 tables and 4 footnotes.)