Part of a special section on English language learners (ELLs). To provide effective instruction for ELLs in mainstream classrooms, Freeport Public Schools on Long Island, New York, merged two distinct professional development strategies. This school district combined the lesson study approach, which involves experienced teachers examining their teaching practices to improve effectiveness, and the Sheltered Instruction Observation Protocol, which involves teachers modifying grade-appropriate curriculum to facilitate learning for ELLs. Further information on the implementation and outcomes of this approach to meeting the needs of ELLs and their teachers is provided.