The purpose of this study is to investigate infant peer interactions and teachers' support for peer interactions in play and daily context in 1-year-old classrooms. The participants of the study were 74 infants and 18 teachers at daycare centers in South Korea. Peer interactions were categorized into initiating behavior (positive, negative), response behavior(positive, negative, withdrawal), and teacher support behavior (teacher-centered, infant-centered, groups). As a result of examining infants' social behavior toward peers, positive attempts were observed more than negative attempts. Regarding social response behaviors, overall more positive reactions than negative reactions were observed. In addition, more positive social attempts were observed in the daily context compared to the play context. Findings indicated that teachers predominantly used teacher-centered support strategies but 'infant-centered support' was more used in daily routine context than play context. This study provides implications for the importance of infants’ active social interaction and how to utilize it in the infant curriculum.