Objective: The objective of this study was to examine the efficacy of child cognitive-behavioral therapy (CCBT) versus family CBT (FCBT) in anxiety-disordered youth with high and low comorbid ADHD symptoms. Method: Youth with anxiety disorders (n = 123, aged 8-18) were classified in four groups according to (a) the type of CBT received (child vs. family) and (b) their comorbid ADHD symptoms, measured with the Child Behavior Checklist (CBCL) Attention Problems syndrome scale level (normal vs. [sub]clinical). Severity of anxiety disorders was assessed with Anxiety Disorders Interview Schedule–Child and Parent (ADIS-C/P) version and anxiety symptoms via a 71-item anxiety symptom questionnaire, the Screen for Child Anxiety and Related Emotional Disorders (SCARED-71), before and after CBT, and at 3 months and 1-year follow-ups. Results: Based on the severity of anxiety disorders, children with high ADHD symptoms profit more from FCBT than CCBT in the long term. For children low on ADHD symptoms, and for anxiety symptoms and attention problems, no differences between CCBT and FCBT occurred. Conclusion: Family involvement seems a valuable addition to CBT for children with comorbid anxiety and ADHD symptoms.