Speech-language pathologists (SLPs) are experiencing the exciting challenge of serving increasing numbers of English Language Learners (ELLs) in U.S. schools. When ELLs struggle in school, they may be overreferred for speech-language services. SLPs are routinely expected to differentiate a language difference based on cultural, linguistic, and environmental characteristics from an underlying primary language impairment (PLI). This tutorial is designed to guide researchers and practicing professionals in the selection of research-based best practices for assessment and intervention for ELLs with potential PLI.