The overarching purpose of this document is to define a new vision for mathematics instruction that explicitly attends to the needs of English Language Learners (ELLs), addressing the interdependence of language and mathematics. The sections in this report are devoted to (1) making clear that the grade-level college- and career-readiness mathematics standards are for ALL students, including ELLs, ELLs who require special education services, and any other students who face learning challenges in mathematics related to language needs; (2) articulating a theory of action in which ELL academic achievement improves when teachers provide all students with grade-level instruction, requiring a high caliber of materials and lessons that present high cognitive demand; (3) identifying and providing instructional principles and practices designed to address the language demands in the new standards for mathematics that may pose challenges for students who are developing both English proficiency and academic language in mathematics; and (4) providing criteria for the selection of instructional materials for mathematics that attend to academic language development and the language demands of the new standards for mathematical practices, so that ELLs and other students with language-related needs have access to grade-level content and practices as set by these standards. This document is designed for educators who are teaching mathematics to ELLs, whether in mainstream/general education classes, in self-contained classes for ELLs, or in other instructional contexts. It may also be used by teachers of students who have a high-incidence disability (e.g., Specific Learning Disability) and an Individualized Education Plan (IEP), or who have unfinished learning in mathematics due to language-related needs. This document is meant to be a useful guide for anyone who is involved in the design, development, and/or selection of curriculum, materials, and resources, whether in a district's central office or at the school level.