PURPOSE: To examine the levels and associations of differentiation of self based on Bowen's theory and adult attachment in a sample with anxiety-related disorders. DESIGN AND METHODS: One hundred fourteen adults with anxiety-related disorders and 117 age- and gender-matched controls were recruited. Levels of differentiation of self, adult attachment, and trait and state anxiety were assessed. FINDINGS: Adults with anxiety-related disorders showed significantly lower global levels of differentiation of self after controlling for socio-demographic characteristics. Adults with anxiety-related disorders also displayed significantly higher levels of anxiety and avoidant attachment. PRACTICE IMPLICATIONS: These constructs may be appropriate targets for intervention research in the study of anxiety-related disorders.