In this chapter, the authors present a synthesis of the small, but growing, body of literature examining what some teacher educators are already doing and what all teacher educators need to do to prepare mainstream classroom teachers to teach English language learners (ELLs). While the discussion applies to teachers of immigrant and refugee students who are ELLs, the authors focus their attention on language-related issues, which have received considerably less attention than cultural issues. They first make the case for preparing all teachers to teach ELLs by examining the growing trend toward the inclusion of ELLs in mainstream classes and the role of language in schooling. They then present a conception of linguistically responsive teaching that outlines essential content for a teacher preparation curriculum designed to prepare teachers for ELLs. Next, they highlight elements of program design that can support the preparation of mainstream teachers to teach ELLs. They conclude with a summary of key points and recommendations for policy and research. (Contains 1 figure.)