Background: ROS1 rearrangements define a subset of non–small-cell lung cancers (NSCLCs) that are susceptible to therapeutic ROS1 kinase inhibition. Despite the fact that most patients initially respond to the first-generation ROS1 tyrosine kinase inhibitor (TKI) crizotinib, relapse invariably occurs, and therapeutic options upon disease progression are limited. Patients and Methods: We conducted a multicenter study of patients with ROS1-rearranged NSCLC who progressed on ROS1 TKIs and examined the clinical outcomes based on the post-progression treatment approaches. Results: Among 29 patients with ROS1-rearrangement who received at least 1 ROS1 inhibitor, the median age was 51 years (range, 30-80 years), 70.8% of patients were female, and 68.9% were never-smokers. Upon progression to the first TKI, 11 patients (37.9%) received treatment with TKIs beyond progression. The median second progression-free survival to TKIs in patents treated beyond progression was 5.5 months (95% confidence interval [CI], 4.1-9.1 months), whereas the post-progression survival was 21.0 months (95% CI, 5.5 months-not reached [NR]). Eleven (37.9%) patients received a sequential treatment with lorlatinib ROS1 TKIs following a first generation ROS1 TKI. The overall response rate, median progression-free survival, and median overall survival (OS) to next-generation TKIs were 41.7% (95% CI, 15.2%-72.3%), 12.7 months (95% CI, 8.5 months-NR), and 17.0 months (95% CI, 15.8 months-NR), respectively. Patients treated with sequential ROS1 TKIs had a significantly longer median OS compared with those who were not (NR vs. 16.1 months; hazard ratio, 0.26; 95% CI, 0.10-0.78; P = .017). Conclusion: In this study, we reported that a subset of patients with ROS1-rearranged NSCLC may benefit from treatment with TKIs beyond progression and that sequential treatment with crizotinib followed by lorlatinib is associated with improved OS in patients with ROS1-rearranged NSCLC. © 2020 Elsevier Inc. Although most of ROS1-rearranged non–small-cell lung cancers respond to treatment with crizotinib, acquired resistance occurs in virtually all patients. Mechanisms of resistance to crizotinib are heterogenous, and therapeutic options upon disease progression are limited. In this study, we demonstrated that sequential crizotinib followed by lorlatinib is associated with improved survival outcomes in patients with ROS1-rearranged advanced non–small-cell lung cancer, with a combined median progression-free survival to sequential crizotinib-lorlatinib of 33.6 months and median overall survival that was not reached at median follow-up of 39.2 months. We also demonstrated that a fraction of patients may benefit from treatment beyond Response Evaluation Criteria in Solid Tumors v1.1 progressive disease, with a median second progression-free survival (after TKI) of 5.5 months and a post-progression survival of approximately 25.2 months. © 2020 Elsevier Inc.