Summary The presented article has two main aims. Firstly, the presentation of the current way of understanding selective mutism (SM), and secondly, — the description of a patient’s therapy based on the cognitive-behavioural model. The main symptom of SM is selectivity of speaking, which applies to specific environments or people. The way selective mutism is classified and treated has been changing in recent years. What is more, researchers dealing with SM have still not established a coherent model of development and persistence of this disorder. In the DSM-5 classification, selective mutism has been moved from the category “disorders of childhood and adolescence” to the subsection of anxiety disorders. The main aim of the implemented change was to emphasize the leading role of fear in the development and persistence of SM. Cognitive-behavioural therapy of mutism is perceived as treatment of choice and to a great extent is related to overcoming a child’s fear of speaking. Because of a limited number of studies, models of therapy based on case reports, and the diversity of clinical pictures, the psychotherapist must adjust the standard model of cognitive-behavioural therapy to a particular patient. Because of the fact that most research is based on case studies, there is a great need for both research on a larger scale and for testing the efficacy of psychotherapy. Currently, the access to qualified therapists is very limited, and the low consciousness of the need for help (especially for children) definitely needs to be changed.