We investigated the associations between students' perceptions of their teachers' management of peer relations (TMPR) and two facets of the peer ecology: perceptions of peer support and the behaviors of popular peers (responsibility and rebelliousness). Participants were 1,031 fifth graders nested within 50 elementary school classrooms. Early adolescents in our sample were majority White and varied in socioeconomic status. A confirmatory factor analysis demonstrated that TMPR was a unique component of adolescents' classroom context. Multilevel modeling indicated that TMPR is positively associated with supportive peer interactions and perceptions that responsible peers are popular. Additionally, TMPR was associated with weaker endorsements that rebellious peers are popular. Findings underscore the importance of teacher practices that are attentive to peer relationships as well as the promise of developing intervention efforts in this area.