In this article, a theoretical model of the role of parental intrusiveness in the development of childhood separation anxiety disorder is presented and tested. Parents who act intrusively tend to take over tasks that children are (or could be) performing independently, thereby limiting mastery experiences and inducing dependence on caregivers. Families of children diagnosed with an anxiety disorder, aged 6-13 years, participated (N = 40). Child anxiety was assessed with a diagnostic interview and rating scales. A novel measure of intrusiveness based on behavioral observations and self-reports was developed, following seven principles for enhancing the psychometric properties of parenting measures. There was initial evidence of strong psychometric properties for the intrusiveness measure, which was associated with children's separation anxiety symptoms, but as predicted, not with other types of anxiety symptoms. Parental intrusiveness appears to be specifically linked with separation anxiety among children with anxiety disorders.