Purpose In two phase III studies, nivolumab, a programmed death-1 (PD-1) inhibitor antibody, improved overall survival (OS) versus docetaxel in pretreated advanced non-small-cell lung cancer (NSCLC). We report 5-year follow-up results from an early phase I study of nivolumab in this patient population and describe characteristics of 5-year survivors. Patients and Methods Patients with pretreated, advanced NSCLC received nivolumab 1, 3, or 10 mg/kg every 2 weeks in 8-week cycles for up to 96 weeks. OS from the time of first dose was estimated by the Kaplan-Meier method. Results The estimated 5-year OS rate was 16% for all treated patients (N = 129); 5-year OS rates were similar for squamous (16%) and nonsquamous (15%) NSCLC. Of 16 5-year survivors, most (88%) were known current or former smokers. Of 10 5-year survivors with quantifiable PD-1 ligand 1 expression, 70% had ≥ 1% PD-1 ligand 1 expression at baseline. Twelve 5-year survivors (75%) achieved a partial response to nivolumab per Response Evaluation Criteria in Solid Tumors, version 1.0, and two each (12%) had stable disease and progressive disease as best response. Nine 5-year survivors (56%) completed the maximum 96 weeks of nivolumab; four (25%) discontinued owing to adverse events and three (19%) owing to disease progression. As of a November 2016 database lock, 12 5-year survivors (75%) received no subsequent therapy and were without evidence of progressive disease at last follow-up. Conclusions Nivolumab treatment resulted in long-term OS and durable responses in a proportion of patients with pretreated advanced NSCLC. Long-term survivors had diverse baseline and on-treatment characteristics.