The goal of the current study was to investigate whether children's social information processing (SIP) predicts their conversations with peers, including both their remarks to peers and peers' remarks to them. When children (N = 156; 55% male; United States; Representation by Race: 60% African American, 18% Mixed race, 15% European American, 7% Other; Representation by Latino/a Ethnicity: 22% Latino/a, 78% Not Latino/a; M[subscript income] = $39,419) were 8 years old, we assessed their aggressive and prosocial SIP using the Social Information Processing Application (SIP-AP). When children were 9 years old, they participated in playgroups typically consisting of four same-sex unfamiliar children who interacted in a round-robin format. Each dyad completed a five-minute frustration task and a five-minute planning task. Observers coded children's verbalizations into six prosocial categories (Suggest, Agree, Solicit Input, Ask, Encourage, State Personal) and four antisocial categories (Command, Disagree, Discourage, Aggress). Children with higher aggressive SIP made more antisocial and fewer prosocial statements, whereas children with higher prosocial SIP made more prosocial and fewer antisocial statements. Furthermore, children with higher aggressive SIP elicited more antisocial and fewer prosocial statements from peers, whereas children with higher prosocial SIP elicited more prosocial and fewer antisocial statements from peers. Children's antisocial and prosocial remarks mediated relations between their aggressive SIP and peers' subsequent antisocial and prosocial remarks. Findings are discussed in terms of: (a) the use of SIP to predict more subtle social behaviors in children's social interaction, and (b) cycles of social interactions that maintain and reinforce children's SIP patterns.