Five hundred five children (267 female) enrolled in school years 5 and 6 in the UK (M = 9 years and 9 months) completed measures of trust beliefs in peers, best friendships, ascriptions of trustworthiness, and trustworthiness toward peers. Children's social disengagement, peer preference, and peer victimization were assessed by sociometric ratings. It was found that, relative to children with consistent trust beliefs and trustworthiness, and those with inconsistent low trust beliefs and high trustworthiness, children with high trust beliefs in peers and low trustworthiness toward peers showed (1) low reciprocity of trustworthiness as assessed by disparity in ascribed trustworthiness between best friends, (2) low quality of peer relationships in the form of low peer preference and high peer victimization, and (3) high social disengagement. The findings supported the basis, domain, and target interpersonal trust framework (Rotenberg) as an account of the relation between children's interpersonal trust consistency and quality of peer relationships. (Contains 5 figures and 2 tables.)