BACKGROUND: Understanding behavioral avoidance associated with generalized anxiety disorder (GAD) has implications for the classification, theoretical conceptualization, and clinical management of the disorder. This study describes the development and preliminary psychometric evaluation of a self-report measure of avoidant behaviors associated with GAD: the Worry Behaviors Inventory (WBI). METHODS: The WBI was administered to treatment-seeking patients (N=1201). Convergent validity was assessed by correlating the WBI with measures of GAD symptom severity. Divergent validity was assessed by correlating the WBI with measures of general disability and measures of depression, social anxiety and panic disorder symptom severity. RESULTS: Exploratory and confirmatory factor analyses supported a two-factor structure (Safety Behaviors and Avoidance). Internal reliability was acceptable for the 10-item WBI scale (α=.86), Safety Behaviors (α=.85) and Avoidance subscales (α=.75). Evidence of convergent, divergent, and discriminant validity is reported. WBI subscales demonstrated differential associations with measures of symptom severity. The Safety Behaviors subscale was more strongly associated with GAD symptoms than symptoms of other disorders, whereas the Avoidance subscale was as strongly correlated with GAD severity as it was with depression, social anxiety and panic disorder severity. LIMITATIONS: Structured diagnostic interviews were not conducted therefor validity analyses are limited to probable diagnoses based on self-report. The cross-sectional design precluded examination of the WBI's temporal stability and treatment sensitivity. CONCLUSIONS: Preliminary evidence supports the use of the WBI in research and clinical settings and may assist clinicians to identify behaviors that are theorized to maintain GAD and that can be targeted during psychological treatment.