By integrating the life history theory of attachment with resource control theory, the current study examines the hypothesis that insecure attachment styles reorganized in middle childhood are alternative adaptive strategies used to prepare for upcoming competition with the peer group. A sample of 654 children in the second through seventh grades in Shanghai, China, participated in this study. The children reported attachment relationships with their mother and the use of resource control strategies in the peer group. Boys had higher avoidant attachment scores than girls, whereas girls had higher ambivalent attachment scores than boys. Moreover, avoidant attachment was positively associated with the use of coercive strategies to control resources. Ambivalent attachment was associated with the use of both coercive and prosocial strategies to control resources. A number of other gender and developmental differences were also observed. The implications for the adaptiveness of insecure attachment in middle childhood are discussed. (Contains 2 tables and 1 figure.)