Equity-centered preparation builds novice teachers' capacity to make meaningful instruction accessible to all students, particularly those historically excluded from high-quality learning experiences. Drawing on social learning theory, we examined Teacher Study Groups as a model for supporting preservice special educators' development of equity-centered practices. We examined 60 preservice teachers' instruction prior to and following study group participation, embedded in a fieldwork support course, alongside related artifacts shared during weekly sessions. Using a convergent mixed-methods approach, we analyzed quantitative and qualitative data separately and then integrated findings using joint display analysis; in doing so, we generated meta-inferences regarding how teachers' attitudes mediated growth in practice. We uncovered salient participatory experiences that influenced--and hindered--professional growth. Our findings have implications for programs interested in structuring professional learning in a manner that builds foundations for an equity-centered practice.