INTRODUCTION: The impact of an immune checkpoint inhibitor (ICI)-based systemic treatment strategy with or without local radical treatment (LRT) on outcomes for patients with NSCLC and synchronous oligometastatic disease (sOMD) is unknown. METHODS: Multicenter retrospective study including adequately staged patients, with sOMD NSCLC (maximum five metastases in three organs [European Organization for Research and Treatment of Cancer definition]) between January 1, 2015 and December 31, 2022, treated with a first-line ICI-based versus chemotherapy-only regimen. Primary end points were progression-free survival and overall survival (OS) for an ICI-based versus chemotherapy-only strategy. Subgroup analyses were performed for patients who were deemed candidates for LRT in the multidisciplinary meeting and those proceeding to LRT. RESULTS: A total of 416 patients were included, treated with chemotherapy-ICI (n = 138) or chemotherapy-only (n = 278), 319 out of 416 were deemed candidates by multidisciplinary meetings for LRT, whereas 192 (60%) proceeded to LRT. The median OS was significantly longer in the chemotherapy-ICI compared with the chemotherapy-only group (33.6 versus 15.9 mo, hazard ratio [HR] = 0.5, 95% confidence interval [CI]: 0.4-0.7, CONCLUSIONS: An ICI-based systemic treatment strategy (±LRT) is associated with improved survival compared with chemotherapy-only (±LRT) for patients with sOMD NSCLC. Prospective randomized trial data are necessary to identify patients most likely to benefit from adding LRT.