This study examined the reactions of 6 to 12 year old children (N = 144) to in-group members who accepted or rejected them, and assessed whether their reactions were influenced by their rejection sensitivity (RS) and social acumen (SA). After completing measures of RS and SA, children participated in an intergroup simulation in which they were accepted or unambiguously versus ambiguously rejected by their group. Findings indicated that whereas ambiguously rejected children understood that they had been rejected, they nevertheless retained greater in-group identification and more positive attitudes than the rejected children, although less than the accepted children. However, as with rejected participants, ambiguously rejected children still opted to change groups whereas accepted children did not. SA children liked the in-group less, whereas those with SA liked the in-group more. Discussion focused on children's selection of peer groups, as well as the effects of their rejection from them.