The present study conducts a systematic investigation of the encoding of countability in three grammatical systems in Mandarin Chinese, including the nominal system, the whpronoun system, and the quantifier system. We examine the countability of linguistic expressions from these three grammatical systems, comparing their countability in the presence/absence of a classifier. A common pattern is identified: classifiers determine the countability of linguistic expressions in the three systems. Our account thus represents a syntactic account of the count-mass in Chinese. We support this theoretical account with three sets of experimental data in Mandarin-speaking adults, and show that the data also militate against the opposing semantic account. The present study contributes new data to the investigation of the count-mass issue in Chinese, and the count-mass issue in general.