Selective mutism (SM) is an anxiety disorder in children/adolescents, characterized by the absence of speaking in specific social situations, mostly at school. The selective mutism questionnaire (SMQ) is a parent report, internationally used to assess SM symptomatology and treatment outcomes. Since no assessment instrument for SM was available in the Netherlands, our aim was to investigate the psychometric properties of the Dutch translation of the SMQ, through reliability, confirmatory factor, and ROC analyses conducted on data obtained in 303 children (ages 3–17 years; clinical SM group n = 106, control group n = 197). The SMQ turned out to be highly reliable (α = 0.96 in the combined sample; 0.83 within the clinical group) and followed the expected factor structure. We conclude that the Dutch version of the SMQ is a reliable and valid tool both as a screening and clinical instrument to assess SM in Dutch speaking children.