School subjects differ in their histories, epistemologies, and relations to state and federal policies. Though educational policymaking is shaped by how education leaders view school mathematics--what mathematics is, how mathematics is learned, and what counts as equitable and high-quality mathematics education--policy research often takes a subject-neutral perspective, ignoring the ways in which policymaking is rooted in the subject-matter. In this article, I report the ways in which systems of meaning or "discourses" about school mathematics penetrate the policymaking of two school districts. Based on a discourse analysis of interviews, observations, and artifacts, I found five main discourses about school mathematics reflected in district policymaking: (1) mathematics is a "core" school subject; (2) mathematics is "sequential," where mastery of prior learning is necessary for future learning; (3) mathematics is "well-defined," with agreement over the content; (4) there are competing perspectives of high-quality mathematics pedagogy, between conceptually-oriented instruction and direct instruction focused on procedures; and (5) equity in mathematics is access and achievement. These discourses about school mathematics were written in formal policy texts, institutionalized in district-wide practices for assessment, intervention, and tracking, and reflected in leaders' personal views and social narratives from teachers, parents, and the community. By making visible the taken-for-granted meanings about school mathematics shaping educational policymaking, it becomes possible to interrupt and challenge them with alternative discourses.