Secondary teachers and leaders, many of whom are implementing the Common Core State Standards, are seeking guidance about how to implement disciplinary literacy practices. Of the four core subjects taught in secondary schools--English, history, math, and science--the authors have found through their work with secondary teachers that math teachers are least likely to be offered support in learning about, designing, and refining disciplinary literacy practices, despite the highly specialized and prevalent literacy practices that math demands. Literacy work in math classrooms remains underspecified and underexplored. This article describes how a team of high school math teachers in Massachusetts participated in a two-year exploration of disciplinary literacy in content classrooms and, as a result, designed instructional routines in math classes that are sensitive to and supportive of students' development of the literacy skills necessary for mathematics.