In this study, we investigated how an experienced fourth-grade teacher responded to her students' thinking as part of her teacher noticing practice in a formative assessment context. Our primary purpose in doing this work was to decompose the responding component of teacher noticing and use our findings to present an emerging framework characterizing the multidimensional nature of this practice. We present two key outcomes based on the findings of this work. First, we show how a formative assessment context situated outside of instruction can engage teachers in practice-based noticing. Second, we present an emerging framework of the responding component of teacher noticing and discuss how it can be used by teacher educators to engage teachers in analytic work in ways that reveal the relationships between what teachers see in students' thinking and how, when, and toward whom they respond.