Objectives: Selective mutism (SM) is a rare, debilitating condition usually seen in children. Selective mutism is typically found in more girls than boys at a young age, which is unlike many of the childhood disorders. Selective mutism cases have a high prevalence of comorbid psychiatric disorders. The specific manifestations and severity of these comorbidities vary based on the individual. Results: Here, we report a rare case of a Turkish adolescent male with intellectual disability (ID) presenting continuous mutism for about 2 years. Conclusion: He had significant improvement in his social interactions after the addition of psycho-educational and behavioural interventions to his fluoxetine treatment. The case is discussed in light of the related literature.