Selective mutism (SM) is a type of anxiety disorder that involves the persistent failure to speak in contexts where speech is typically expected (e.g., school), despite speaking in other contexts (e.g., home). Research on the etiology and treatment of SM is limited, as it is a rare disorder and few clinical trials evaluating SM interventions have been conducted. Far less is known about the diagnosis and treatment of SM in children who are acquiring a second language. This article will present guidelines for the assessment and treatment of SM in children who are English language learners (ELLs), as informed by a case study and a thorough review of research literature. Evidence-based guidance for school professionals working with ELL students who exhibit symptoms of SM will be provided.