Selective mutism (SM) is a developmental disorder characterized by a child’s inability to speak in certain contexts and/or in the presence of unfamiliar interlocutors. This work proposes a critical discussion of the most recent studies on SM, with respect to clinical and diagnostic features, as well as the etiology and treatment of this disorder. At present, all research work supports the hypothesis that SM is a complex anxiety disorder with multifactorial etiology (interaction among biological and environmental causes). The latest edition (...) of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5; American Psychiatric Association, 2013) places SM mutism among “Anxiety Disorders”, and no longer among “Other Childhood, Infant and Adolescent Disorders” (as in DSM-IV). Other important aspects relate to cognitive biases and emotional states at the base of SM, which partly explain the disorder’s persistence and represent an important objective of intervention work. No data in the literature point to a total remission of SM, but good results are achieved with cognitive behavior intervention and multimodal therapy (MMT) involving a variety of child interaction contexts. (shrink)