The ability to categorize emotions has long-term implications for children's social and emotional development. Therefore, identifying factors that influence early emotion categorization is of great importance. Yet, whether and how language impacts emotion category development is still widely debated. The present study aimed to assess how labels influence young children's ability to group faces into emotion categories for both earliest-learned and later-learned emotion categories. Across two studies, 128 two- and 3-year-olds (77 female; Mean age = 3.04 years; 35.9% White, 12.5% Multiple ethnicities or races, 6.3% Asian, 3.1% Black, and 42.2% not reported) were presented with three emotion categories (Study 1 = happy, sad, angry; Study 2 = surprised, disgusted, afraid). Children sorted 30 images of adults posing stereotypical facial expressions into one of the three categories. Children were randomly assigned to either hear the emotion labels before sorting (e.g., "happy faces go here") or were not given labels (e.g., "faces like this go here"). Study 1 results indicated no significant effects of labels for earlier-learned emotion categories, F(1, 60) = 0.94, p = 0.337, [eta][subscript p][superscript 2] = 0.013. However, the Study 2 results revealed that labels improved emotion categorization for later-learned categories, F(1, 60) = 8.15, p = 0.006, [eta][subscript p][superscript 2] = 0.024. Taken together, these results suggest that labels are important for emotion categorization, but the impact of labels may depend on children's familiarity with the emotion category.