Objectives: Control beliefs are well-established predictors of anxiety symptomatology, yet existing models emphasize the protective effects of high perceived control without considering the influence of individual differences in metacognitive appraisals of control—namely, the evaluation of the control one believes to have and the control they desire to have. In the present study, we propose that control discrepancy (i.e., the subjective appraisal of the misalignment between perceived and desired control) is a distinct metacognitive vulnerability factor for generalized anxiety disorder (GAD). Methods: In a large non-clinical sample (N = 1,325; M age = 35.9, SD = 16.0), we examined whether control discrepancy predicted elevated GAD risk and greater GAD symptom severity beyond traditional control constructs. Participants completed validated measures assessing mental health symptoms and control beliefs. Results: Results from LASSO-regularized logistic and generalized ordered logistic regressions revealed that control discrepancy was a significant predictor of both GAD risk and symptom severity. Notably, perceiving more control than desired presented a particularly elevated risk, even at high levels of perceived control. These associations remained robust after adjusting for depressive symptoms, perceived stress, perceived control, desired control, and their interaction. Conclusion: Findings provide initial evidence of control discrepancy as a distinct control belief that is uniquely associated with GAD symptomatology beyond that of perceived control, desired control, and their interaction. These results call for a re-evaluation of interventions that primarily target increasing perceived control and underscore the clinical potential of tailoring treatment to reduce control discrepancy, particularly when perceived control greatly exceeds desired control.