<p>This paper examines a constraint that penalizes the presence of a monosyllabic object when the preceding verb is disyllabic. The effect of this syllabicity constraint has long been observed in Mandarin, and there have been different approaches to explaining its nature. However, whether this constraint operates in other Chinese dialects remains understudied. This paper provides empirical evidence for the syllabicity constraint in Wenzhounese, a southern Wu dialect. The data from Wenzhounese are illuminating in two respects. First, Wenzhounese has a rich tonal system that provides independent support for the stress-based analysis of the syllabicity constraint. Second, violating the syllabicity constraint in Wenzhounese only results in degraded grammaticality but not ungrammaticality, which challenges linguistic frameworks that consider grammaticality to be binary. Building on these observations, I provide a stress-based analysis of the syllabicity constraint which is more restrictive than previous analyses in that it is intrinsically local and it does not directly refer to syntactic information.</p>