We contend that previous work on children's identification with social groups has looked at the mere categorization of the self in group terms and not subjective identification properly conceived. Drawing upon self-categorization theory, the present research operationalizes identification as self-stereotyping (i.e. the ability to conceive of the self in group-relevant terms). Children's self-stereotyping was explored in two studies using gender as the relevant ingroup. Study 1 required 5-, 7- and 10-year-old children, on two separate occasions, to rate their similarity to, and difference from, same-sex peers. Relative to the control condition, when gender had been made salient, children perceived significantly greater similarity, and smaller difference, between themselves and same-sex peers, thus providing evidence of a capacity for self-stereotyping and, hence, for subjective identification with a social category. Similarly, Study 2 sought trait ratings of the self both when gender had been made salient and when it had not. Boys of all ages (though not girls) rated ingroup-stereotypical traits (such as bravery and strength) to be more characteristic of the self when gender was salient than when it was not. Together, these findings suggest that the capacity for subjective identification with social groups is present at least by the age of 5 years. Moreover, they demonstrate that children's self-conceptions are contextually variable.