Selective mutism is a psychiatric disorder in which children without significant language difficulties persistently fail to speak in a variety of social situations, typically school. The addition of selective mutism into the anxiety disorders category of DSM-5, defining it as a severe developmental variant of social anxiety disorder, mandates the need to develop best practice guidelines that incorporate evidence from the literature and clinician consensus for assessment and treatment. This Special Interest Study Group brings together clinicians and researchers to discuss the changes in the classification and diagnostic criteria for selective mutis, review current research on assessment and treatment, and discuss developing consensus for best assessment and treatment. Attendees actively participate, sharing their experiences working with selective mutism.