Visual appearance is one of the main cues children rely on when categorizing novel objects. In 3 studies, testing 128 3-year-olds and 192 5-year-olds, we investigated how various kinds of information may differentially lead children to overlook visual appearance in their categorization decisions across domains. Participants saw novel animals or artifacts of varying degrees of similarity to target categories and were asked to place them in 1 of 2 categories. Manipulated across studies was the kind of information pitted against visual similarity: internal information (Study 1, both 3- and 5-year-olds), intentional information (Study 2, both 3- and 5-year-olds), or labels (Study 3, only 5-year-olds). Overall, we found that for 5-year-olds, but not so for 3-year-olds, internal information had a stronger effect on the categorization of animals than of artifacts. Intentional information, in turn, had a stronger effect on both age groups' categorization of artifacts than of animals. Labels too had a stronger effect on 5-year-olds' categorization of artifacts than of animals. These findings are consistent with a domain-specific account of categorization, according to which the weight of different kinds of information on categorization decisions depends on children's developing understanding of domains.