The current study aimed to examine the relation between experiential avoidance and anxiety disorders, as well as the usefulness of the Avoidance and Fusion Questionnaire for Youth (AFQ-Y; Greco, Lambert, & Baer, 2008) in detecting anxiety disorder in a sample of adolescent inpatients. First, the relation between experiential avoidance and anxiety among inpatient adolescents was investigated from categorical and dimensional points of view, making use of self-report and parent report, as well as clinical interview, while controlling for depression and externalizing problems. Second, we sought to establish the clinical utility value of the AFQ-Y by determining the sensitivity, specificity, and clinical cutoff score of this measure in predicting anxiety disorder. To this end, a sample of inpatient adolescents (N = 111) with a mean age of 16.14 (SD = 1.39) years completed the AFQ-Y, alongside interview- and questionnaire-based measures of psychopathology. Results showed a significant relation between anxiety disorder and experiential avoidance, independent of depression. Receiver operating characteristics analysis revealed that the AFQ-Y has moderate accuracy (area under the curve = .815, SE = .047, p < .001) in discriminating adolescents with a diagnosis of any anxiety disorder (cutoff score 26.5; sensitivity = .74, specificity = .76). Given the comorbidity of anxiety and depression in this sample, this cutoff is not indicative of pure anxiety disorder but may be helpful in predicting those with emotional disorders in general.