Our purpose was to explore developmental changes in the organization and access to the mental lexicon between the ages of three-, five-, and seven years. Six-hundred and seventy three Mandarin-speaking participants listed all exemplars of animals and foods that came to mind within two one-minute intervals. Compared to younger participants, the older children demonstrated more correct responses and fewer errors, suggesting that they have greater knowledge of category-relevant vocabulary. They produced more subcategories, many of which involved embedding and overlapping, which suggests they have more sophisticated lexical-semantic organization. Also, they produced fewer and less closely spaced repetitions, suggesting they could more effectively monitor retrieval responses. We conclude that between the ages of three to seven, children expand and refine the organization of their mental lexicons. Improved monitoring may reflect growth in executive functioning.