According to self‐categorization theory (Oakes, Haslam, & Turner, 1994), stereotypes vary to reflect variations in the comparative context within which they are formed. In this study we explore stereotype variability in a sample of 5‐ and 7‐year‐old children. Participants described a specific out‐group, and then described the in‐group (that is ‘boys’ or ‘girls’, depending on the sex of the participant). Description was provided by judging the proportion of group members to whom each trait from a list was seen as applicable. There were two experimental conditions: in the first condition the outgroup was represented by adult ‘men’ if participants were boys, or by adult ‘women’ if participants were girls. In the second condition the out‐group was represented by ‘girls’, if participants were boys, or by ‘boys’, if participants were girls. Descriptions of the in‐group were found to differ significantly with changes in the frame of reference amongst both 5‐ and 7‐year‐olds, though more for boys than girls. Overall, such findings challenge the widely held view that stereotypes are endemically stable cognitive structures.