Research Findings: The aim of this study was to explore the relations between children's trust beliefs and social competence as well as social preference. In addition, this study examined how children with different trust belief profiles may differ in their peer interactive behaviors. A total of 47 children ages 5 to 6 participated in this study. Data were collected via observation of play behaviors, a teacher-rated social competence scale, and a child interview. The results indicated that children's trust beliefs in friends' promise-keeping behaviors were positively associated with intrapersonal and interpersonal domains of social competence. Children who had greater trust in non-friend classmates' promise-keeping behaviors tended to be sociable in a group, polite, and more preferred, and they were less likely to be disliked by peers. Children with different trust profiles exhibited differential interactive behaviors with peers. Practice or Policy: These findings suggest that parents and early childhood educators should pay more attention to the extent to which young children trust their close friends and familiar peers, especially in terms of keeping promises. Adults may model their efforts in keeping their promises made to children and enhance children's capacity to reciprocate trust in close relationships. Adults can help children differentiate their trust based on the intimacy of relationships.