This 3-year qualitative study examined how 26 teachers in four U.S. secondary schools addressed the literacy demands of curriculum materials based on standards from the National Council of Teachers of Mathematics. It was grounded in sociocultural perspectives that encourage study of language in local contexts, including classrooms, communities, and disciplines. The research question asked, "How do secondary mathematics teachers in a teacher--researcher collaboration understand and address the literacy demands of standards-based curriculum materials?" An interdisciplinary team of literacy and mathematics education researchers and graduate students worked with teachers to examine required curriculum materials, plan lessons, and share resources, while collecting qualitative data to capture teachers' understandings and actions. Findings indicated that teachers responded in three ways to the materials' literacy demands: (a) they used the materials selectively to bypass or reduce the literacy demands, (b) they augmented use of the materials with literacy support, or (c) they integrated use of the materials into long-term frameworks to develop mathematics and literacy learning simultaneously. The study suggests the value of using insights from mathematics and literacy to inform mathematics curriculum design and reminds us to take teachers' perspectives toward such materials seriously, particularly when they collaborate to address issues about the materials' use in their own school contexts.