Teaching practices that are responsive to student thinking are complex and challenging to learn, particularly for novice teachers. Skilled responsive teaching involves adaptive expertise, or the ability to deliberate about and respond to students' emergent ideas. This study explored the learning of early-career teachers through participation in a video-feedback inquiry group around the enactment of a number talk routine introduced in preservice teacher education. Conceptualizing teacher learning as socially situated within a discourse community, we consider how participation in the asynchronous inquiry group supported both collective interpretations and individual growth in implementing responsive instructional practices. Findings suggest that giving and receiving asynchronous feedback provided novice teachers with opportunities to engage in dialogic conversations that involved several types of deliberation related to responsive teaching and the development of adaptive expertise. This study provides evidence of the potential of asynchronous teacher inquiry groups and the importance of giving, as well as receiving, feedback on practice.