Drawing on interviews with a diverse sample of teachers, this study uses the frame of professional identity to interpret the heterogeneity among teachers' perceptions of professional development. Specifically, it examines how teachers' "anchoring beliefs" might be reflected in or refracted by their accounts of powerful professional learning. An analysis of three case studies of teacher identity and teacher learning reveals three distinct "learning affinities": for the what (content), the who (facilitation), and the with whom (community). This learning affinity framework may better model teachers' experiences of professional development and thus could point the way toward improved research and design.