ObjectiveTo systematically review the efficacy of antibiotics on the outcomes of patients with non-small cell lung cancer (NSCLC) treated with immune checkpoint inhibitors. MethodsPubMed, EMbase, Web of Science, The Cochrane Library, CNKI, WanFang Data, VIP and CBM databases were electronically searched to collect cohort studies on efficacy of antibiotics on the outcomes of patients with NSCLC treated with immune checkpoint inhibitors from inception to August 1st, 2021. Two reviewers independently screened literature, extracted data, and evaluated the risk of bias of the included studies. Meta-analysis was then performed by using RevMan 5.3 software. ResultsA total of 27 cohort studies involving 7 087 patients were included. The results of meta-analysis showed that antibiotic use was associated with poor overall survival (OS) (HR=2.04, 95%CI 1.68 to 2.49, P<0.000 01) and progression free survival (PFS) (HR=1.63, 95%CI 1.35 to 1.99, P<0.000 01). ConclusionCurrent evidence shows that antibiotic use is associated with poor OS and PFS. Due to the limited quality and quantity of the included studies, more high-quality studies are needed to verify the above conclusion.