Selective mustism (SM) is an anxiety disorder that manifests in childhood. Children with Children with SM do not speak in certain social situations where this is expected of them. For example, a child may talk at home, but is afraid to speak at school. The goal of this clinical trial is to determine the efficacy of behavioral therapy for children with selective mutism (SM) combined with virtual reality (VR) homework exercises. Virtual Reality Exposure is an effective treatment for adults with anxiety disorders. The main questions to answer are: * Is behavioral therapy combined with VR homework exercises effective in the treatment of SM? * Which familial factors contribute to a positive treatment outcome and homework adherence? A single-case experimental design (SCED) will be used to evaluate the efficacy of the treatment. The child's speaking behavior at baseline will be compared to the child's speaking behavior in the different phases of the intervention. Participants will: * Follow individual therapy sessions at school. * Practice with the VR homework exercises at least once a week. * Parents and teachers will evaluate the child's speaking behavior.