Many schools and school districts are implementing sheltered instruction to help serve the needs of English Language Learners (ELLs) in mainstream content-area classes. Sheltered instruction is a research-based instructional framework that provides clear and accessible content and academic language to ELLs in pre-K-12 grade-level classes. Programs such as Sheltered Instruction Observation Protocol (SIOP) assess and measure implementation of sheltered instruction and are used in staff development with both English as a Second Language (ESL) teachers and content-area, mainstream teachers to promote use of sheltered techniques in grade-level classes. Sheltered instruction combines both tried-and-true instructional techniques that characterize what experienced educators know as good teaching practices and instruction specially designed to meet the linguistic and educational needs of immigrant and nonimmigrant second-language learners in U.S. schools. This article provides an overview of sheltered instruction, shows how it can be implemented in mainstream classes, and encourages its implementation in pre-K-12 grade-level classrooms.