This study contributes to a growing body of literature focused on the role of the teacher's "invisible hand" in managing students social relationships. The authors focus on one specific aspect of attunement, teachers' social network knowledge, which they conceptualize as the completeness and accuracy of the teacher's social network knowledge, which they conceptualize as the completeness and accuracy of the teacher's perceptions of students' peer affiliation patterns. Two premises of this work are that: (a) teachers who possess accurate network knowledge are in a better position to manage peer relationships in ways that support a positive classroom climate and achievement motivation; and (b) network knowledge is a potentially malleable element of teaching quality which can be targeted for professional development. Because past research suggests that hierarchical social structures in classrooms may contribute to a negative climate, the authors were especially interested in understanding whether teachers with better network knowledge might counteract the negative effect of social hierarchies. (Contains 2 tables and 1 figure.)