In this study we investigate young children's knowledge of syntactic constraints on Noun Phrase reference by testing 30-month-olds' interpretation of two types of transitive sentences. In a preferential looking task, we find that children prefer different interpretations for transitive sentences whose object NP is a name (e.g., "She's patting Katie") as compared with those whose object NP is a reflexive pronoun (e.g., "She's patting herself"). They map the former onto an other-directed event (one girl patting another) and the latter onto a self-directed event (one girl patting her own head). These preferences are carried by high-vocabulary children in the sample and suggest that 30-month-olds have begun to distinguish among different types of transitive sentences. Children's adult-like interpretations are consistent with adherence to Principles A and C of Binding Theory and suggest that further research using the preferential looking procedure to investigate young children's knowledge of syntactic constraints may be fruitful.