Background: Clinical staging of lung cancer may not reliably predict nodal disease, and its accuracy in The Society of Thoracic Surgeons General Thoracic Surgery Database is not described. Methods: Among anatomic pulmonary resections for stages I to III lung cancer with complete clinical and pathologic staging (2012-2017), the accuracy of invasive mediastinal staging (IMS) was compared with noninvasive mediastinal staging only. Accuracy, defined as concordance between clinical and pathologic nodal status, was examined using logistic regression to determine factors associated with clinical nodal (cN) accuracy. Variation in accuracy across centers was recorded and categorized. Results: We included 39,516 patients with stages I to III pulmonary cancer (adenocarcinoma, 66%; squamous, 23%; neuroendocrine, 5%; mixed, 3.3%; other, 2.4%), of whom 90.4% had cN0 disease. IMS was performed in 32.4%. The IMS group had more central tumors (14.8% vs 6.0%, P <.001) and cN1-2 (15.7% vs 6.8%, P <.001). Nodal accuracy was 79.8%. Although IMS had a lower nodal accuracy for cN0-2 disease (74.6% vs 82.6%, P <.001), IMS had higher accuracy when comparing patients with cN1-2 disease (53.9% vs 46.9%, P <.001). In multivariable analysis central tumors (odds ratio, 0.47; 95% confidence interval, 0.43-0.51) and >cN0 disease (odds ratio, 0.25; 95% confidence interval, 0.22-0.29) were associated with lower accuracy. Accuracy of IMS in the top 20 centers was 94.4% and in the bottom 20, 70.9%. Conclusions: Staging accuracy in lung cancers selected for initial resection declines with >cN0 and central tumors. Noninvasive staging in tumors without cN involvement misses nearly 20% of cN1-2. Center-specific accuracy is a target for quality improvement.