Segmentectomy for lung cancer has been increasingly performed. However, evidence regarding the necessity of additional surgical resection following the diagnosis of unsuspected N1/N2 lymph node metastasis is limited. We conducted a multicenter real-world data study of patients with clinically any T and N0 non-small cell lung cancer (NSCLC) who underwent lobectomy or segmentectomy between 2012 and 2021 and were subsequently diagnosed with pathological N1/N2 lymph node metastasis. Patients were categorized into lobectomy and segmentectomy groups. We analyzed overall survival (OS), recurrence-free survival (RFS), cumulative recurrence rates, and recurrence patterns using both unadjusted and propensity score-adjusted cohorts. A total of 736 patients were in the lobectomy group, and 70 in the segmentectomy group. In the unadjusted cohort, segmentectomy patients were older and had lower preoperative percent vital capacity, smaller tumors, and received less postoperative adjuvant chemotherapy. The 5-year OS was significantly worse in the segmentectomy group (P=0.011), with no significant differences in 5-year RFS or cumulative recurrence rates. In the propensity score-adjusted cohort, there were no significant differences in OS, RFS, or recurrence rates; however, the segmentectomy group had a higher rate of local recurrence. In patients with unsuspected N1/N2 NSCLC, analysis using a cohort adjusted for patient background with propensity scores revealed no differences in OS, RFS, or cumulative recurrence rates between segmentectomy and lobectomy. This suggests that additional resection of the remaining segments may not be necessary for these patients. However, the higher rate of local recurrence in the segmentectomy group warrants careful consideration.