Because most English language learners receive instruction in content-area classes, teachers of these classes need to understand the varying backgrounds of ELLs and their different levels of conversational and academic English skills. The authors have developed a research-based model for effectively delivering sheltered instruction to ELLs in mainstream classrooms. This model identifies effective strategies for promoting academic English literacy among ELLs. Strategies include identifying the language demands of the content course, planning language objectives for all lessons and making them explicit to students, emphasizing academic vocabulary development, identifying and strengthening background knowledge, and reviewing vocabulary and content concepts.