The school nurse plays a pivotal role in the assessment and treatment of selective mutism (SM), a rare disorder found in elementary school children. Due to anxiety, children with SM do not speak in uncomfortable situations, primarily the school setting. Diagnosis of SM is often missed in the formative years because the child does speak at home. Early diagnosis and treatment provide the key to addressing this rare disorder. The school nurse plays a critical role as a member of the Instructional Support Team (IST). The school nurse, as team liaison, provides communication between parents, school staff, and medical personnel. School nurses make a difference by advocating for the child with SM and possessing the necessary knowledge to effectively intervene. This article discusses a team approach to the assessment and treatment of SM and the role of the school nurse in the school setting. (Contains 6 resources and 3 online resources.)