Selective mutism (SM) is a relatively rare childhood disorder characterized by a consistent failure to speak in specific settings (e.g., school, social situations) despite speaking normally in other settings (e.g., at home). The latest edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) lists SM among the anxiety disorders. This makes sense as the current review of the literature confirms that anxiety is a prominent symptom in many children suffering from this condition. Further, research on the etiology and treatment of SM also corroborates the conceptualization of SM as an anxiety disorder. At the same time, critical points can be raised regarding the classification of SM as an anxiety disorder. We explore a number of such issues in this review. Recommendations for dealing with this diagnostic conundrum are made for psychologists, psychiatrists, and other mental health workers who face children with SM in clinical practice, and directions for future research are highlighted.