Three studies are reported that assess 5, 7- and 10-year-old children's cognitive inclusion of the ingroup in the self. Each study investigated a different ingroup: gender, family, and age group. Children were shown sets of cards identifying particular trait adjectives and were asked to rate the extent to which the traits applied to the self, the ingroup, and the outgroup. After a distraction task, they were asked to remember for whom (self, ingroup, or outgroup) each trait had been rated. In all studies and for all age groups, the authors found that traits rated for the self were confused more frequently with traits rated for the ingroup than with traits rated for the outgroup. It is concluded that, at least from the age of 5 years, psychologically relevant ingroups have become integral pairs of the self-system.