Research Findings: This research examines preschoolers' use of mental state terms in naturally occurring peer conflicts in the classroom to determine how children use mental state terms for organizing their social interactions. Analyses focus on the types, frequencies, and social interactive functions of mental state terms. Utterances (N = 166) with mental state terms from 124 conflict episodes were analyzed. Children used a number of different mental state terms, "want" and "need" being the most frequently used, to index their own and their interlocutors' desires for subtle interactive purposes. "Want" was paired most often with bids for action, objects, inclusion in a play area, or clarification of another child's mental state. "Need" was most often used when directing the other child's action or attention, to justify, clarify, or insist on their own action or previous request. Practice or Policy: Findings suggest that children's peer conflicts constitute a rich setting for the active construction of social relationships through the use of utterances with mental state language. This emphasis on peer interactions has the potential to inform new ways of supporting children's self--other development as a foundation for academic success.