Developing ambitious and equitable mathematics teaching involves recognizing and working against fundamentally inequitable hierarchies that pervade the dominant culture of US schools. To engage in this sizeable undertaking, teachers need ongoing, work-embedded opportunities for learning and thought partners with whom to do it. Instructional coaching is increasingly employed as a strategy to support improvement in mathematics teaching, but little is known about how coaching can function to support this the kind of teacher learning required for the development of more ambitious and equitable math classrooms. Moreover, in much research on teacher learning, and almost all research on coaching, learning itself is either underspecified or narrowly articulated, and goals for teacher learning leave out equity.

This dissertation introduces and operationalizes a multi-strand framework for transformative teacher learning toward ambitious and equitable teaching (in short, TTL), and employs it to investigate possibilities for coaching to support this learning. Interactions between two middle school math teachers and their coach were observed and recorded and surveys and interviews were conducted. Close examination of the work of these two teacher-coach pairs yield findings with implications for the research and practice of equity-focused coaching.

All strands of learning were found to support the others, and when barriers existed in individual strands, their consequences were broadly evident. One teacher engaged in learning along all strands, coming, in her own words, to be “wowed” by her students’ mathematical thinking. This story of learning involved making new meaning of students, mathematics, and teaching; coming to engage deeply in coaching; co-participating with the coach in risky, new classroom practice; developing an articulated vision of powerful teaching; coming to identify as competent with respect to that vision; and developing joint engagement with the coach. One teacher experienced challenging power and positioning with respect to her coach, and this arrangement inhibited all strands of her TTL. When power was renegotiated and new positions established, opportunities for each aspect of TTL were newly available. In both cases, learning was found to be afforded and constrained by frames for coaching, and the joint accomplishment of productive reframing was found to involve opportunities for participation that is inconsistent with extant, less productive frames.

Findings support articulation of some aspects of powerful coaching, as well as challenges that coaches must navigate. Three broad and interrelated coaching practices were found to support TTL: (1) working from the premise, made explicit in talk, that each student is mathematically smart; (2) naming and building from teachers’ strengths related to ambitious and equitable teaching; and (3) interrogating mathematical content. However, as TTL was found to be mediated by power and cultural frames for coaching, these practices alone were insufficient. Coaching toward TTL was found to necessitate attention to issues of culture, power, and framing that mediate teachers’ experiences in coaching interactions. These findings have implications for the preparation and support of coaches and the design of coaching programs intended to support teacher learning toward ambitious and equitable teaching.