Gender and age are salient social categories from early in development. However, whether children's beliefs about gender and age intersect, such that gender stereotypes might be expressed differently when asked about children (compared to adults) has not been investigated. Here, in a preregistered study (N = 297), we examined if young children (3.0-6.9-year-olds, M[subscript age] = 5.03 years, n = 145) and adults (n = 152) across Massachusetts were more likely to express gender stereotypes when presented with child or adult stimuli. Participants were presented with 20 questions about gender stereotyped behavioral and psychological properties and selected their response (male or female) for each question by selecting between four child faces (two White boys, two White girls) or four adult faces (two White men, two White women) across two separate blocks. Overall, both children and adults expressed gender stereotypes above chance, and, in children, expression of stereotypes increased across the age range. Although neither children nor adults applied gender stereotypes differently to child versus adult visual stimuli, all participants were more likely to apply gender stereotypes when that stereotype was child-centric (e.g., about doing childish activities). Our results suggest that children could be vulnerable to stereotype content from an early age; however, future research should explore whether children show this same age-invariant pattern when both gender and age are made salient and directly contrasted (e.g., by presenting men, women, boys, and girls simultaneously).