Frailty has been widely recognized as a predictor of postoperative outcomes. Given the paucity of standardized frailty measurements in thoracic procedures, this study aimed to determine the impact of coding-based frailty on clinical outcomes and resource use after anatomic lung resection. All adults undergoing elective, anatomic lung resections (segmentectomy, lobectomy, pneumonectomy) from 2005 to 2014 were identified using the National Inpatient Sample. Patients were categorized as either frail or nonfrail on the basis of the presence of any frailty-defining diagnoses defined by the Johns Hopkins Adjusted Clinical Groups. Multivariable models were used to assess the independent association of frailty with in-hospital mortality, nonhome discharge, complications, duration of stay, and costs. Of an estimated 366,357 hospitalizations for elective lung resection during the study period, 4.4% were in frail patients. Patients who underwent pneumonectomy or were treated at low-volume hospitals were more commonly frail. Relative to nonfrail patients, frailty was associated with increased unadjusted mortality (9.1% vs 1.7%; P < .001) and nonhome discharge (44.7% vs 10.5%; P < .001). Frail patients had 3.47 increased adjusted odds of mortality across resection types (95% confidence interval, 2.94 to 4.09). Frailty conferred the greatest increase in mortality, complications, and resource use after pneumonectomy relative to lobectomy or segmentectomy, although significant differences were evident for all 3 operations. Frailty exhibits a strong association with inferior clinical outcomes and increased resource use after elective lung resection, particularly pneumonectomy. This readily available tool may improve preoperative risk assessment and allow for better selection of treatment modalities for frail patients with pulmonary disorders.