This study qualitatively explores expertise as a critical resource on which quality teaching depends. The study sample is comprised of six South African schools from the poorest poverty quintiles achieving relatively higher and lower academic outcomes. From interview data gathered over three years with teachers and other school staff, findings reveal significant differences between schools in the kinds of expertise that circulate in teacher communities. Remediation strategies that support student learning at specific levels of complexity stand out as a significant form of expertise. In schools performing above demographic expectations, teachers have more opportunities to access knowledge as an instructional resource, enabled by the recognition of differences in expertise. The study offers insight into what kinds of pedagogic strategies might disrupt educational inequalities and support the quality of teaching and learning within a system of scarce resources.