IntroductionClinical information regarding selective mutism (SM), a persistent and debilitating psychiatric disorder, in children is extremely limited. We aimed to examine sociodemographic characteristics and comorbid psychiatric conditions and identify clinical variables associated with sex and SM severity among children with SM.MethodsWe analyzed the medical records of 49 children who received treatment for SM in four different tertiary hospitals in Turkey between 2016 and 2021. Children's charts were reviewed to examine clinical characteristics, comorbidities, and response to treatment.ResultsThirty-one children were female, and 18 were male (female:male ratio is 1.7:1). Most children (73.5%) with SM displayed onset of SM in 3-6 years. However, most children (57.1%) were diagnosed between the ages of 7-11. The mean time from onset to diagnosis was 1.69 +/- 1.37 years. Females displayed a later onset of SM (6.42 +/- 2.40 vs. 4.89 +/- 0.96; p= 0.013) and higher comorbidity rates (71% vs. 38.9%, p= 0.039) than males. The vast majority of children received two or more psychiatric diagnoses. Children in the severe group had a longer duration of illness, higher rates of psychiatric comorbidity, speech delay, and treatment resistance.ConclusionOur study suggests that SM may have different clinical features according to sex and symptom severity of SM. More information about children with SM is needed to understand the development and maintenance of SM.