There is substantial evidence documenting the impact of high-quality, educative learning materials on teacher practices and student learning, yet this evidence has not translated widely into more equitable learning opportunities for all students. English learners tend to have less access to intellectually rich, grade-level content and instructional materials. With most English learners receiving instruction for math and English language arts alongside their non-English learner peers, it can no longer be the norm to simplify the content or rely on supplemental materials targeting English learners. Instructional materials must be well-designed to serve all students. What do materials that do this well look like, and how do teachers know know if theirs measure up? The English Learners Success Forum, an organization working to enhance instructional materials to address the linguistic and cultural needs of English learners, convened national English learner experts, field-leading content providers, and educators to examine how to integrate English learner supports in English language arts and math materials. Guidelines and tools created to determine if materials measure up are presented in this article.