Despite the prominence of teaching in academia, we know little about how graduate students learn to teach. We propose the concept of a teaching community network (TCN), an informal social network that facilitates the exchange of teaching-specific resources. We explore the role of TCNs through a case study of a sociology doctoral program at a large state university. Results reveal that students rely heavily on informal ties within the graduate student community and existing formal programs to share teaching-related resources (e.g., information and social support) and develop their identities as instructors. We suggest that graduate programs facilitate TCNs through formal teacher-training programs and structural conditions that encourage informal, one-on-one interactions (e.g., shared offices). By cultivating TCNs, graduate programs can assist students in developing their teaching skills and identities as instructors, thus training students to balance the demands of research and teaching within an academic culture. (Contains 2 tables and 2 figures.)