Children’s social-emotional behaviors become early predictors of cognitive and social-emotional development. Nevertheless, children’s interactions in their natural context have not received much attention. This naturalistic qualitative study examined children’s social-emotional behaviors in their peer interactions during play. The participants in this study were 39 children across three different preschool programs in the US. Through a qualitative analysis, three frequent and significant behaviors stood out in children’s peer interactions. These were classified as power, teamwork, and social-emotional difficulties. This qualitative study provides information and knowledge that can be used to inform pre-service and in-service teachers about young children’s peer interactions in the classroom. Its results can help increase teachers’ understanding of patterns in children’s peer interactions within their play and enlighten teachers’ roles in the classroom to better support children’s social-emotional development.